Human structure. Bones of the head (skull). Cerebral part of the skull What is the parietal bone of the skull responsible for?

The human brain is a complex evolutionary achievement that requires special protection provided by the bones of the cranial vault. One of them, the parietal bone, is a convex quadrangular segment. Injuring it can lead to serious consequences, which are reversible in some cases if the victim receives professional assistance in a timely manner.

Structure of the parietal bone

Like some other skull fragments, the parietal bone is paired and has a flat shape. The left and right segments are located symmetrically, connected to each other, and fit quite tightly to the brain tissue, which explains their convex-concave shape.

Important! There are no tubular or spongy bones in the skull, only flat and mixed ones.

The protruding outer surface of the bone is relatively smooth, its relief is determined by the need for attachment of soft tissues. The apex of the convexity of the segment is called the parietal tubercle; it is from here that the process of ossification of the pliable membrane tissue of the human embryo begins. Under these formations are the temporal lines. The upper one serves to attach the temporalis fascia, the lower one – the temporalis muscle. The inner, curved surface has grooves that copy the relief of the venous sinuses and the membrane of the brain. The connections between bone and adjacent fragments are called sutures.

• The sagittal suture is the articulation of the serrated edges of the two parietal bones with each other. Towards the back of the sagittal suture there is an opening for a vein on the parietal bone;
• The frontal and occipital edges, which have the same jagged structure, are connected to the frontal and occipital bones, forming the coronoid and lambdoid sutures;
• The lower edge has a scaly shape, is beveled and covered by the edges of the sphenoid bone, forming a scaly suture. Two connections - the sphenoid-parietal and parietal-mastoid sutures, are formed by the overlap of the parietal edge of the temporal bone and its mastoid process.

In anatomy, the vertices of an improvised quadrilateral, the shape of which is the parietal bone, are called angles. The connections of the corners of three or more flat bones form fontanelles - membranous (in the first months of life) areas of the skull that ossify (ossify) subsequently.

• The frontal angles (upper anterior) of the vertex bones are straight, forming the anterior fontanelle at the intersection of the sagittal and coronal sutures;
• The rounded obtuse occipital angles (posterior superior) in the area of ​​convergence of the lambdoid sutures with the sagittal suture form the posterior fontanelle;

• The connection of the mastoid, obtuse angles (posterior lower) with the occipital and temporal bones is called the mastoid fontanelle;
• The wedge-shaped (anterior lower) acute angle, connecting with the temporal bone, sphenoid and frontal, creates an H-shaped connection - a wedge-shaped fontanelle, vulnerable to force even after reaching adulthood.

Functions

The parietal bone, like the other bones of the cranial vault, protects the brain from any damage and harmful environmental influences.

Formation of the parietal bone

The membranous tissue covering the rudiments of the embryonic brain is gradually replaced by bone. Unlike, for example, the ethmoid bone, which is formed from cartilage, the parietal fragment of the skull bypasses the cartilaginous stage. At approximately the 7th week of embryo development, in the place where the parietal tubercle is “planned” (the largest convexity of this zone), the rudiments of the future bone arise from the connective tissue.

Merging with each other, they grow, and ossification occurs radially - from the center towards the edges. Ossification of the segment is completed in the first months of human life: the areas farthest from the middle (angles) harden, which, connecting with other bones of the skull, form fontanelles in the newborn. The elastic tissues of the fontanelles leave vulnerable spots on the head, but have a very important function: they provide the necessary deformation of the child’s skull during birth and during the rapid development of the brain.

It happens that the parietal bone is divided into two or more fragments.

Pathologies of the parietal bone

The causes of deviations may be hereditary, associated with intrauterine development or complications during childbirth.

• Hyperosto

Thickening of the parietal bone due to layers of bone tissue. The pathology is harmless and does not affect the patient’s appearance; moreover, it is often discovered by chance based on the results of radiography or computed tomography (CT).

• Craniosynostosis

This is premature fusion of the cranial bones. The occurrence of pathology can be explained by heredity or abnormalities of intrauterine development. The degree of deformation of the skull depends on the period of fusion of the cranial sutures. The most pronounced distortions of the shape occur if the overgrowth took place in the womb. Depending on the location of the pathology, the following forms of craniosynostosis are distinguished.

• Scaphocephaly. The head is compressed from the sides, while elongated in the direction from the forehead to the back of the head. Occurs in the case of fusion of the sagittal suture;
• Turricephaly is a protrusion of the temporal bones, along with a narrowing of the rest of the skull. Caused by closure of the sagittal and coronal sutures;
• Brachycephaly is premature fusion of the lambdoid suture with the coronoid suture. Leads to an increase in the width of the skull;
• Trigonocephaly. It appears due to the early closure of the metopic suture connecting the halves of the frontal lobes. The skull takes on a teardrop shape, with a convexity in the forehead.

Limitation of the volume of the cranium can lead to hypertension (increased intracranial pressure), which is detected in a newborn by a combination of the following signs:

• vomit;
• high-pitched scream;
• convulsions;
• muscle hypertonicity;
• sluggish sucking;
• bulging of the fontanelles, lack of pulse in them;
• eye rolling;
• dilation of veins on the scalp.

Craniosynostosis can lead to serious pathologies and developmental abnormalities - from difficulty breathing to visual impairment or joint disease. Pathology is diagnosed by visual examination and treated surgically.

• Cephalohematoma

Cephalohematoma refers to birth injuries, but in itself is not a bone pathology - it is an accumulation of blood that is located between the periosteum (a thin layer of connective tissue covering the outside of the skull) and the skull itself. In advanced cases, ossification may occur.

Most often, hemorrhage occurs in a newborn if he is injured due to compression of the head during a difficult birth. Passing through the birth canal of a woman with a narrow pelvis or using obstetric instruments during childbirth can lead to the formation of a hematoma. Poor blood clotting in newborns complicates the situation. The baby's blood gradually (up to 3 days) accumulates in the damaged area. The following scenarios are possible:

• A small hematoma that will resolve without outside intervention;
• In case of extensive hematoma, puncture (here: removal of contents) and application of a pressure bandage with further observation by a pediatrician and pediatric surgeon are necessary;
• If the cephalohematoma is accompanied by damage to the skin of the skull, a course of antibiotics is prescribed, otherwise suppuration may occur, which will also require surgical intervention;
• An extensive hematoma can ossify over time, distorting the shape of the skull. In this case, the ossified tissue is excised and the edges of the wound are sutured. The child should be systematically examined by a surgeon and neurologist for at least another year from the date of surgery.

Cephalohematoma is diagnosed by visual examination or ultrasound. Externally, the formation looks like a lump: large hemorrhages can follow the contour of the bone, making a frightening impression on an unprepared viewer. When palpated, the soft, elastic bulge will hurt, which the child will signal by crying or trying to defend himself with his hands.

Osteoma of the skull

The pathology is an exophytic (i.e., in an outward direction) slow, benign growth of bone tissue. Causes include heredity, syphilis, gout, and rheumatism. There is no threat to the brain, due to the specific location of the tumor, and it does not develop into a malignant one. Hypertension, absent-minded attention, and memory impairment are sometimes noted.

The aesthetic defect is eliminated along with a certain amount of bone tissue after X-ray or CT scanning. The resulting cavity is filled with artificial materials.

Parietal bone injuries

A common occurrence in human life is a broken bone. Its cause is a mechanical impact in any of its manifestations: a blow with a hard, non-sharp object, compression, a fall on the head from a height, a wound - this is an incomplete list of options for the origin of the injury.

A fracture has the following symptoms:

• severe pain at the site of injury;
• hematoma;
• scalp wound (detachment of the scalp or tendons);
• edema formation;
• loss of consciousness (not always).

The classification of skull fractures is described below.

• Depressed fractures. The bone fragment exerts a compressive effect on the brain. Possible consequences of injury include hematomas, crushing of the brain, damage to its blood supply system;
• Linear fractures. They are characterized by the corresponding form of damage – cracks. No bone displacements occur, however, the danger lies in the likelihood of hemorrhages in the spaces between the skull bone and the dura mater;
• Comminuted fractures. They are recognized as the most dangerous, since bone fragments can damage brain tissue, which threatens the loss of some of its functions, depending on the location and extent of the damage.

If a fracture of the skull bones is detected, you should immediately call an ambulance: only a study will allow you to assess the nature of the damage, provide a prognosis and prescribe the necessary treatment.

The skeleton of the head, that is, the skull (cranium) (Fig. 59), consists of the brain and facial skull.

Rice. 59. Skull A - front view; B - side view:1 - parietal bone;2 - frontal bone;3 - sphenoid bone;4 - temporal bone;5 - lacrimal bone;6 - nasal bone;7 - zygomatic bone;8 - upper jaw;9 - lower jaw;10 - occipital bone

The brain skull is ovoid in shape and is formed by the occipital, frontal, sphenoid, ethmoid, a pair of temporal and a pair of parietal bones. The facial skull is formed by six paired bones (upper jaw, lower turbinate, lacrimal, nasal, zygomatic and palatine bones) and three unpaired bones (lower jaw, hyoid bone, vomer) and represents the initial section of the digestive and respiratory apparatus. The bones of both skulls are connected to each other using sutures and are practically motionless. The lower jaw is connected to the skull by a joint, therefore it is the most mobile, which is necessary for its participation in the act of chewing.

The cranial cavity is a continuation of the spinal canal and contains the brain. The upper part of the brain skull, formed by the parietal bones and the scales of the frontal, occipital and temporal bones, is called the vault or roof of the skull (calvaria cranii). The bones of the cranial vault are flat, their outer surface is smooth and even, and the inner surface is smooth, but uneven, since it contains grooves of arteries, veins and adjacent convolutions of the brain. Blood vessels are located in the spongy substance - diploe, located between the outer and inner plates of the compact substance. The inner plate is not as strong as the outer one, it is much thinner and more fragile. The lower part of the skull, formed by the frontal, occipital, sphenoid and temporal bones, is called the base of the skull (basis cranii).

Brain bones

The occipital bone (os occipitale) (Fig. 59) is unpaired, located in the posterior part of the cranium and consists of four parts located around the large foramen (foramen magnum) (Fig. 60, 61, 62) in the antero-inferior part of the outer surface.

The main, or basilar, part (pars basilaris) (Fig. 60, 61) lies anterior to the external opening. In childhood, it connects to the sphenoid bone with the help of cartilage and sphenoid-occipital synchondrosis (synchondrosis sphenooccipitalis) is formed, and in adolescence (after 18–20 years) the cartilage is replaced by bone tissue and the bones grow together. The upper inner surface of the basilar part, facing the cranial cavity, is slightly concave and smooth. It contains part of the brain stem. At the outer edge there is a groove of the inferior petrosal sinus (sulcus sinus petrosi inferior) (Fig. 61), adjacent to the posterior surface of the petrous part of the temporal bone. The lower outer surface is convex and rough. In its center is the pharyngeal tubercle (tuberculum pharyngeum) (Fig. 60).

The lateral, or lateral, part (pars lateralis) (Fig. 60, 61) is paired and has an elongated shape. On its lower outer surface there is an ellipsoidal articular process - the occipital condyle (condylus occipitalis) (Fig. 60). Each condyle has an articular surface through which it articulates with the first cervical vertebra. Behind the articular process there is a condylar fossa (fossa condylaris) (Fig. 60) with a non-permanent condylar canal (canalis condylaris) located in it (Fig. 60, 61). At the base, the condyle is pierced by the hypoglossal canal (canalis hypoglossi). On the lateral edge there is a jugular notch (incisura jugularis) (Fig. 60), which, combining with the same notch of the temporal bone, forms the jugular foramen (foramen jugulare). The jugular vein, glossopharyngeal, accessory and vagus nerves pass through this opening. At the posterior edge of the jugular notch there is a small protrusion called the jugular process (processus intrajugularis) (Fig. 60). Behind it, along the inner surface of the skull runs a wide groove of the sigmoid sinus (sulcus sinus sigmoidei) (Fig. 61, 65), which has an arched shape and is a continuation of the groove of the same name in the temporal bone. Anterior to it, on the upper surface of the lateral part, there is a smooth, gently sloping jugular tubercle (tuberculum jugulare) (Fig. 61).

Rice. 60. Occipital bone (external view):

1 - external occipital protrusion; 2 - occipital scales; 3 - upper nuchal line; 4 - external occipital crest; 5 - lower nuchal line; 6 - large hole; 7 - condylar fossa; 8 - condylar canal; 9 - side part; 10 - jugular notch; 11 - occipital condyle; 12 - jugular process; 13 - pharyngeal tubercle; 14 - main part

The most massive part of the occipital bone is the occipital scales (squama occipitalis) (Fig. 60, 61, 62), located behind the foramen magnum and taking part in the formation of the base and vault of the skull. In the center on the outer surface of the occipital scales there is an external occipital protuberance (protuberantia occipittalis externa) (Fig. 60), which is easily palpable through the skin. From the external occipital protrusion to the foramen magnum the external occipital crest (crista occipitalis externa) is directed (Fig. 60). Paired upper and lower nuchal lines (linea nuchae superiores et inferiores) (Fig. 60), which represent a trace of muscle attachment, extend to both sides of the external occipital crest. The upper nuchal lines are at the level of the outer protrusion, and the lower ones are at the level of the middle of the outer ridge. On the inner surface, in the center of the cruciform eminence (eminentia cruciformis), there is an internal occipital protuberance (protuberantia occipittalis interna) (Fig. 61). Down from it, down to the foramen magnum, the internal occipital crest (crista occipitalis interna) descends (Fig. 61). A wide, gentle groove of the transverse sinus (sulcus sinus transversi) runs to both sides of the cruciform eminence (Fig. 61); The groove of the superior sagittal sinus (sulcus sinus sagittalis superioris) runs vertically upward (Fig. 61).

Rice. 61. Occipital bone (inside view):

1 - occipital scales; 3 - internal occipital protrusion; 4 - groove of the transverse sinus; 5 - internal occipital crest; 6 - large hole; 8 - condylar canal; 9 - jugular process; 10 - groove of the inferior petrosal sinus; 11 - side part; 12 - main part

The occipital bone is connected to the sphenoid, temporal and parietal bones.

The sphenoid bone (os sphenoidale) (Fig. 59) is unpaired and is located in the center of the base of the skull. The sphenoid bone, which has a complex shape, is divided into a body, small wings, large wings and pterygoid processes.

The body of the sphenoid bone (corpus ossis sphenoidalis) has a cubic shape, with six surfaces. The upper surface of the body faces the cranial cavity and has a depression called the sella turcica (sella turcica), in the center of which is the pituitary fossa (fossa hypophysialis) with the lower appendage of the brain, the pituitary gland, located in it. In front, the sella turcica is limited by the tubercle of the sella (tuberculum sellae) (Fig. 62), and behind by the dorsum of the sellae (dorsum sellae). The posterior surface of the body of the sphenoid bone is connected to the basilar part of the occipital bone. On the anterior surface there are two openings leading into the air-bearing sphenoid sinus (sinus sphenoidalis) and called the aperture of the sphenoid sinus (apertura sinus sphenoidalis) (Fig. 63). The sinus is finally formed after 7 years inside the body of the sphenoid bone and is a paired cavity separated by the septum of the sphenoid sinuses (septum sinuum sphenoidalium), emerging onto the anterior surface in the form of a wedge-shaped crest (crista sphenoidalis) (Fig. 63). The lower part of the crest is pointed and represents a wedge-shaped beak (rostrum sphenoidale) (Fig. 63), wedged between the wings of the vomer (alae vomeris), attached to the lower surface of the body of the sphenoid bone.

The small wings (alae minores) (Fig. 62, 63) of the sphenoid bone are directed in both directions from the anterosuperior corners of the body and represent two triangular plates. At the base, the small wings are pierced by the optic canal (canalis opticus) (Fig. 62), which contains the optic nerve and ophthalmic artery. The upper surface of the small wings faces the cranial cavity, and the lower one takes part in the formation of the upper wall of the orbit.

The large wings (alae majores) (Fig. 62, 63) of the sphenoid bone extend to the sides from the lateral surfaces of the body, heading outward. At the base of the large wings there is a round opening (foramen rotundum) (Fig. 62, 63), then an oval (foramen ovale) (Fig. 62), through which the branches of the trigeminal nerve pass, and outward and posteriorly (in the area of ​​the angle of the wing) ) there is a spinous foramen (foramen spinosum) (Fig. 62), which passes through the artery that supplies the dura mater of the brain. The inner, cerebral, surface (facies cerebralis) is concave, and the outer is convex and consists of two parts: the orbital surface (facies orbitalis) (Fig. 62), involved in the formation of the walls of the orbit, and the temporal surface (facies temporalis) (Fig. 63) , participating in the formation of the wall of the temporal fossa. The large and small wings limit the superior orbital fissure (fissura orbitalis superior) (Fig. 62, 63), through which vessels and nerves penetrate the orbit.

Rice. 62. Occipital and sphenoid bones (top view):

1 - large wing of the sphenoid bone; 2 - small wing of the sphenoid bone; 3 - visual channel; 4 - tubercle of the sella turcica; 5 - occipital scales of the occipital bone; 6 - superior orbital fissure; 7 - round hole; 8 - oval hole; 9 - large hole; 10 - foramen spinosum

The pterygoid processes (processus pterygoidei) (Fig. 63) extend from the junction of the large wings with the body and are directed downward. Each process is formed by outer and inner plates, fused in front, and diverging behind and limiting the pterygoid fossa (fossa pterygoidea).

Rice. 63. Sphenoid bone (front view):

1 - large wing; 2 - small wing; 3 - superior orbital fissure; 4 - temporal surface; 5 - aperture of the sphenoid sinus; 6 - orbital surface; 7 - round hole; 8 - wedge-shaped ridge; 9 - wedge-shaped channel; 10 - wedge-shaped beak; 11 - pterygoid process; 12 - lateral plate of the pterygoid process; 13 - medial plate of the pterygoid process; 14 - wing-shaped hook

The internal medial plate of the pterygoid process (lamina medialis processus pterygoideus) (Fig. 63) takes part in the formation of the nasal cavity and ends in the pterygoid hook (hamulus pterygoideus) (Fig. 63). The outer lateral plate of the pterygoid process (lamina lateralis processus pterygoideus) (Fig. 63) is wider, but less long. Its outer surface faces the infratemporal fossa (fossa infratemporalis). At the base, each pterygoid process is pierced by a pterygoid canal (canalis pterygoideus) (Fig. 63), through which vessels and nerves pass.

The sphenoid bone connects to all the bones of the brain skull.

Rice. 64. Temporal bone (external view): 1 - scaly part;2 - zygomatic process;3 - mandibular fossa;4 - articular tubercle;5 - external auditory opening;6 - stony-scaly gap;7 - drum part;8 - mastoid process;9 - styloid process

The temporal bone (os temporale) (Fig. 59) is paired and takes part in the formation of the base of the skull, the lateral wall and the vault. It contains the organ of hearing and balance (see section “Sense Organs”), the internal carotid artery, part of the sigmoid venous sinus, the vestibulocochlear and facial nerves, the trigeminal ganglion, branches of the vagus and glossopharyngeal nerves. In addition, connecting to the lower jaw, the temporal bone serves as a support for the masticatory apparatus. It is divided into three parts: stony, scaly and drum.

Rice. 65. Temporal bone (inside view): 1 - scaly part;2 - zygomatic process;3 - arcuate elevation;4 - drum roof;5 - subarc fossa;6 - internal auditory opening;7 - groove of the sigmoid sinus;8 - mastoid foramen;9 - rocky part;10 - external opening of the vestibule water supply;11 - styloid process

The stony part (pars petrosa) (Fig. 65) has the shape of a three-sided pyramid, the apex of which faces anteriorly and medially, and the base, which passes into the mastoid process (processus mastoideus), faces posteriorly and laterally. On the smooth anterior surface of the stony part (facies anterior partis petrosae), near the top of the pyramid, there is a wide depression, which is the site of the adjacent trigeminal nerve - trigeminal depression (impressio trigemini), and almost at the base of the pyramid there is an arcuate eminence (eminentia arcuata) (Fig. 65), formed by the underlying superior semicircular canal of the inner ear. The anterior surface is separated from the internal stony-scaly fissure (fissura petrosquamosa) (Fig. 64, 66). Between the gap and the arcuate elevation there is a vast area - the tympanic roof (tegmen tympani) (Fig. 65), under which lies the tympanic cavity of the middle ear. Almost in the center of the posterior surface of the stony part (facies posterior partis petrosae), the internal auditory opening (porus acusticus internus) is noticeable (Fig. 65), heading into the internal auditory canal. Vessels, facial and vestibulocochlear nerves pass through it. Above and lateral to the internal auditory opening is the subarcuate fossa (fossa subarcuata) (Fig. 65), into which the process of the dura mater penetrates. Even lateral to the opening is the external opening of the vestibular aqueduct (apertura externa aquaeductus vestibuli) (Fig. 65), through which the endolymphatic duct emerges from the cavity of the inner ear. In the center of the rough lower surface (facies inferior partis petrosae) there is an opening leading to the carotid canal (canalis caroticus), and behind it is the jugular fossa (fossa jugularis) (Fig. 66). Lateral to the jugular fossa, a long styloid process (processus styloideus) extends downwards and anteriorly (Fig. 64, 65, 66), which is the point of origin of muscles and ligaments. At the base of this process there is a stylomastoid foramen (foramen stylomastoideum) (Fig. 66, 67), through which the facial nerve exits the cranial cavity. The mastoid process (processus mastoideus) (Fig. 64, 66), which is a continuation of the base of the petrous part, serves as the attachment point for the sternocleidomastoid muscle.

On the medial side, the mastoid process is limited by the mastoid notch (incisura mastoidea) (Fig. 66), and along its inner, cerebral, side there is an S-shaped groove of the sigmoid sinus (sulcus sinus sigmoidei) (Fig. 65), from which to the outer surface of the skull leads to the mastoid foramen (foramen mastoideum) (Fig. 65), which belongs to the non-permanent venous outlets. Inside the mastoid process there are air cavities - mastoid cells (cellulae mastoideae) (Fig. 67), communicating with the cavity of the middle ear through the mastoid cave (antrium mastoideum) (Fig. 67).

Rice. 66. Temporal bone (bottom view):

1 - zygomatic process; 2 - muscular-tubal canal; 3 - articular tubercle; 4 - mandibular fossa; 5 - stony-scaly gap; 6 - styloid process; 7 - jugular fossa; 8 - stylomastoid foramen; 9 - mastoid process; 10 - mastoid notch

The scaly part (pars squamosa) (Fig. 64, 65) has the shape of an oval plate, which is located almost vertically. The outer temporal surface (facies temporalis) is slightly rough and slightly convex, participates in the formation of the temporal fossa (fossa temporalis), which is the origin of the temporal muscle. The inner cerebral surface (facies cerebralis) is concave, with traces of adjacent convolutions and arteries: digital indentations, cerebral eminences and arterial sulcus. Anterior to the external auditory canal, the zygomatic process (processus zygomaticus) rises sideways and forward (Fig. 64, 65, 66), which, connecting with the temporal process, forms the zygomatic arch (arcus zygomaticus). At the base of the process, on the outer surface of the scaly part, there is a mandibular fossa (fossa mandibularis) (Fig. 64, 66), which provides a connection with the lower jaw, which is limited in front by the articular tubercle (tuberculum articularae) (Fig. 64, 66).

Rice. 67. Temporal bone (vertical section):

1 - the probe is inserted into the facial canal; 2 - mastoid cave; 3 - mastoid cells; 4 - semi-canal of the tensor tympani muscle; 5 - semi-canal of the auditory tube; 6 - the probe is inserted into the carotid canal; 7 - the probe is inserted into the stylomastoid foramen

The tympanic part (pars tympanica) (Fig. 64) is fused with the mastoid process and the scaly part, and is a thin plate that bounds the external auditory opening and the external auditory canal in front, behind and below.

Rice. 68. Parietal bone (external view):

1 - sagittal edge; 2 - occipital angle; 3 - frontal angle; 4 - parietal tubercle; 5 - superior temporal line; 6 - occipital edge; 7 - frontal edge; 8 - lower temporal line; 9 - mastoid angle; 10 - wedge-shaped angle; 11 - scaly edge

The temporal bone contains several canals:

The carotid canal (canalis caroticus) (Fig. 67), in which the internal carotid artery lies. It starts from the outer hole on the lower surface of the rocky part, goes vertically upward, then, bending smoothly, passes horizontally and comes out at the top of the pyramid;

Facial canal (canalis facialis) (Fig. 67), in which the facial nerve is located. It begins in the internal auditory canal, goes horizontally forward to the middle of the anterior surface of the petrous part, where, turning at a right angle to the side and passing into the posterior section of the medial wall of the tympanic cavity, it goes vertically down and opens with the stylomastoid foramen;

The muscular-tubal canal (canalis musculotubarius) (Fig. 66) is divided by a septum into two parts: the semicanal of the tensor tympani muscle (semicanalis m. tensoris tympani) (Fig. 67), and the semicanal of the auditory tube (semicanalis tubae auditivae) (Fig. 67), connecting the tympanic cavity with the pharyngeal cavity. The canal opens with an external opening located between the anterior end of the petrous part and the squama of the occipital bone, and ends in the tympanic cavity.

The temporal bone connects to the occipital, parietal and sphenoid bones.

The parietal bone (os parietale) (Fig. 59) is paired, flat, has a quadrangular shape and takes part in the formation of the upper and lateral parts of the cranial vault.

The outer surface (facies externa) of the parietal bone is smooth and convex. The place of its greatest convexity is called the parietal tubercle (tuber parietale) (Fig. 68). Below the tubercle are the superior temporal line (linea temporalis superior) (Fig. 68), which is the attachment point of the temporal fascia, and the inferior temporal line (linea temporalis inferior) (Fig. 68), which serves as the attachment point of the temporal muscle.

The internal, cerebral, surface (facies interna) is concave, with a characteristic relief of the adjacent brain, the so-called digital impressions (impressiones digitatae) (Fig. 71) and tree-like branching arterial grooves (sulci arteriosi) (Fig. 69, 71).

The bone has four edges. The anterior frontal edge (margo frontalis) (Fig. 68, 69) connects to the frontal bone. Posterior occipital margin (margo occipitalis) (Fig. 68, 69) - with the occipital bone. The upper sagittal, or sagittal, edge (margo sagittalis) (Fig. 68, 69) is connected to the edge of the same name of the other parietal bone. The lower scaly edge (margo squamosus) (Fig. 68, 69) is covered in front by the large wing of the sphenoid bone, a little further - by the scales of the temporal bone, and in the back it connects with the teeth and mastoid process of the temporal bone.

Rice. 69. Parietal bone (inside view): 1 - sagittal edge;2 - groove of the superior sagittal sinus;3 - occipital angle;4 - frontal angle;5 - occipital edge;6 - frontal edge;7 - arterial grooves;8 - groove of the sigmoid sinus;9 - mastoid angle;10 - wedge-shaped angle;11 - scaly edge

Also, according to the edges, four angles are distinguished: frontal (angulus frontalis) (Fig. 68, 69), occipital (angulus occipitalis) (Fig. 68, 69), wedge-shaped (angulus sphenoidalis) (Fig. 68, 69) and mastoid (angulus mastoideus ) (Fig. 68, 69).

Rice. 70. Frontal bone (external view):

1 - frontal scales; 2 - frontal tubercle; 3 - temporal line; 4 - temporal surface; 5 - glabella; 6 - brow ridge; 7 - supraorbital notch; 8 - supraorbital edge; 9 - zygomatic process; 10 - bow; 11 - nasal spine

Rice. 71. Frontal bone (inside view):

1 - groove of the superior sagittal sinus; 2 - arterial grooves; 3 - frontal ridge; 4 - finger indentations; 5 - zygomatic process; 6 - orbital part; 7 - nasal spine

The frontal bone (os frontale) (Fig. 59) is unpaired and participates in the formation of the anterior part of the vault and base of the skull, eye sockets, temporal fossa and nasal cavity. It has three parts: the frontal scales, the orbital part and the nasal part.

The frontal scales (squama frontalis) (Fig. 70) are directed vertically and posteriorly. The outer surface (facies externa) is convex and smooth. From below, the frontal scales end with a pointed supraorbital edge (margo supraorbitalis) (Fig. 70, 72), in the medial section of which there is a supraorbital notch (incisura supraorbitalis) (Fig. 70), containing the vessels and nerves of the same name. The lateral section of the supraorbital margin ends with a triangular zygomatic process (processus zygomaticus) (Fig. 70, 71), which connects to the frontal process of the zygomatic bone. An arcuate temporal line (linea temporalis) runs posteriorly and upward from the zygomatic process (Fig. 70), separating the outer surface of the frontal scales from its temporal surface. The temporal surface (facies temporalis) (Fig. 70) is involved in the formation of the temporal fossa. Above the supraorbital margin on each side is the brow ridge (arcus superciliaris) (Fig. 70), which is an arched elevation. Between and just above the brow ridges there is a flat, smooth area - the glabella (glabella) (Fig. 70). Above each arch there is a rounded elevation - the frontal tubercle (tuber frontale) (Fig. 70). The inner surface (facies interna) of the frontal scales is concave, with characteristic indentations from the convolutions of the brain and arteries. In the center of the inner surface there is a groove of the superior sagittal sinus (sulcus sinus sagittalis superioris) (Fig. 71), the edges of which in the lower section unite into the frontal ridge (crista frontalis) (Fig. 71).

Rice. 72. Frontal bone (bottom view):

1 - nasal spine; 2 - supraorbital edge; 3 - trochlear fossa; 4 - trochlear spine; 5 - fossa of the lacrimal gland; 6 - orbital surface; 7 - trellis cutting

Rice. 73. Ethmoid bone (top view):

2 - lattice cells; 3 - cockscomb; 4 - lattice labyrinth; 5 - cribriform plate; 6 - orbital plate

The orbital part (pars orbitalis) (Fig. 71) is paired, takes part in the formation of the upper wall of the orbit and has the appearance of a horizontally located triangular plate. The lower orbital surface (facies orbitalis) (Fig. 72) is smooth and convex, facing the orbital cavity. At the base of the zygomatic process in its lateral section there is a fossa of the lacrimal gland (fossa glandulae lacrimalis) (Fig. 72). The medial section of the orbital surface contains the trochlear fossa (fovea trochlearis) (Fig. 72), in which the trochlear spine (spina trochlearis) lies (Fig. 72). The upper cerebral surface is convex, with a characteristic relief.

Rice. 74. Ethmoid bone (bottom view):

1 - perpendicular plate; 2 - cribriform plate; 3 - lattice cells; 5 - superior nasal concha

The nasal part (pars nasalis) (Fig. 70) of the frontal bone in an arc surrounds the ethmoid notch (incisura ethmoidalis) (Fig. 72) and contains pits that articulate with the cells of the labyrinths of the ethmoid bone. In the anterior section there is a descending nasal spine (spina nasalis) (Fig. 70, 71, 72). In the thickness of the nasal part lies the frontal sinus (sinus frontalis), which is a paired cavity separated by a septum, belonging to the air-bearing paranasal sinuses.

The frontal bone connects to the sphenoid, ethmoid and parietal bones.

The ethmoid bone (os ethmoidae) is unpaired and participates in the formation of the base of the skull, the orbit and the nasal cavity. It consists of two parts: a lattice, or horizontal, plate and a perpendicular, or vertical, plate.

Rice. 75. Ethmoid bone (side view): 1 - cockscomb;2 - lattice cells;3 - orbital plate;4 - middle turbinate;5 - perpendicular plate

The cribriform plate (lamina cribosa) (Fig. 73, 74, 75) is located in the ethmoidal notch of the frontal bone. On both sides of it there is a lattice labyrinth (labyrinthus ethmoidalis) (Fig. 73), consisting of air-bearing lattice cells (cellulae ethmoidales) (Fig. 73, 74, 75). On the inner surface of the ethmoid labyrinth there are two curved processes: the superior (concha nasalis superior) (Fig. 74) and the middle (concha nasalis media) (Fig. 74, 75) nasal turbinates.

The perpendicular plate (lamina perpendicularis) (Fig. 73, 74, 75) is involved in the formation of the septum of the nasal cavity. Its upper part ends with the cock's crest (crista galli) (Fig. 73, 75), to which the large falciform process of the dura mater is attached.

Parietal bone, os parietale, steam room, forms the middle part of the cranial vault. In humans, it reaches the greatest development in comparison with all animals due to the highest development of his brain. It represents a typical integumentary bone, performing primarily a protective function. Therefore, it has a relatively simple structure in the form of a quadrangular plate, convex on the outside and concave on the inside.

Its four edges serve to connect with neighboring bones, namely: the anterior - with the frontal, margo frontalis, the posterior - with the occipital, margo occipitalis, the medial - with the sonominal bone of the other side, margo sagittalis, and the lateral - with the scales of the temporal bone, margo squamosus . The first three edges are serrated, and the last is adapted to form a scaly suture. Of the four corners, the anteromedial one connects with the frontal bone, angulus frontalis, the anterolateral one with the sphenoid bone, angulus sphenoidalis, the posteromedial one with the occipital bone, angulus occipitalis, and the posterolateral one with the base of the mastoid process of the temporal bone, angulus mastoideus.

The relief of the outer convex surface is caused by the attachment of muscles and fascia. In its center stands the parietal tubercle, tuber parietale (the place of the beginning of ossification). Below it there are curved temporal lines - lineae temporales (superior et inferior) - for the temporal fascia and muscle. Near the medial edge there is an opening, foramen parietale (for artery and vein).

The relief of the internal concave surface, facies interna, is due to the fit of the brain and especially its hard shell; the places of attachment of the latter to the bone look like a groove running along the medial edge of the sagittal sinus, sulcus sinus sagittalis superioris (trace of the venous sinus, sinus sagittalis superior), as well as in the area of ​​the angulus mastoideus transverse groove,

The parietal bone, like all other structures of the human body, has its own anatomical features. They are determined by the tasks the implementation of which is assigned to this area of ​​the skull.

Anatomical structure of the parietal bone

Currently, this aspect is known very, very well. The parietal bone is a kind of quadrangle. This structure has a flattened shape.

The parietal bone is paired. Both of them have absolutely no differences. The left and right parietal bones are connected to each other by their upper edges. They are called sagittal. These edges are fastened with the same seam. The frontal and parietal bones are connected in front. In this case, the first of them is slightly wedged into the second. This is due to the fact that the frontal edge of the parietal bone has a somewhat concave shape.

The lower edge of this anatomical structure is called the squamosal. It is so called because of the slightly varying surface in a given place. This edge connects the parietal bone with the temporal bone.

There is also an occipital edge. It borders on the bone of the same name. This edge has a somewhat convex shape.

In addition, the parietal bone also has 4 edges. The one that is located between the occipital and is called mastoid. Above it is the occipital angle. Between the frontal and temporal bones there is a wedge-shaped angle. Slightly higher from it is the frontal angle.

"Superficial" anatomy

The parietal bone does not have a flat structure. The fact is that its outer surface is convex, and its inner surface, on the contrary, is concave. This anatomical structure of the parietal bone is due to the need for its relatively tight fit to

The outer surface is relatively smooth. As for the interior, it is quite heterogeneous. The fact is that on this surface there is a large number of arterial grooves. They are necessary for additional protection of the vessels supplying blood to such an important organ as the brain.

On the inner surface of the parietal bone in the area of ​​the mastoid angle there is a groove for the sigmoid sinus.

Functions of the parietal bone

First of all, it is part of the skull. The main task of this bone is to protect the skull from any damaging effects of the external environment. First of all, we are talking about protecting the central organ of the entire nervous system from various types of blows and other traumatic influences.

Another important function of the parietal bone is to protect the brain from low temperatures. Also, this role is also played to a certain extent by hair.

About pathology in the structure of the parietal bone

This area often becomes the site of formation of one or another pathological process. Currently, the most common of them are the following:

• osteoma;
• cephalohematoma;
• hyperostosis;
• various types of injuries.

Osteoma

She represents Her feature is the so-called (that is, outward). It is because of this that it does not pose a serious danger to human health. The main problem here can only be a cosmetic defect. This benign tumor grows extremely slowly.

Diagnosis of the disease is carried out using X-ray examination, as well as computed tomography.

As for treatment, it is carried out at the request of the patient by removing part of the parietal bone. If this area exceeds 2 cm 2 in area, then the resulting hole is closed with a special material.

Cephalohematoma

This pathology in the vast majority of cases develops during childbirth. This occurs through the interaction of the skull of a newborn child and the birth canal of his mother. As a result of the constant mechanical impact that is exerted on the parietal bone during childbirth, hemorrhage occurs under the periosteum. Children have significantly less clotting ability than adults, so cephalohematoma can grow over several days. Moreover, due to the anatomical features of this area, such a pathological process never extends beyond the parietal bone.

Diagnosis of cephalohematoma is based on a routine examination, as well as ultrasound examination.

For minor hemorrhages, treatment may not be required. Over time, the resulting cephalohematoma will resolve on its own. If the amount of blood is large enough, then it is necessary to remove it using a puncture. In cases where, in addition to cephalohematoma, there is also damage to the skin, it is necessary to carry out a course of treatment, otherwise significant complications may occur.

Hyperostosis

This deviation from the norm represents the formation of excessive layers on the surface of the parietal bone. As a result, it turns out to be somewhat thicker than usual. This pathology does not have any clinical manifestations. This is the reason for the fact that most often this deviation from the norm becomes an accidental finding during radiography or computed tomography of the skull, prescribed for completely different reasons.

Treatment for hyperostosis is not required. Not only does it not cause harm to health, but it does not even appear as a cosmetic defect.

Injuries

Most often, pathologies of the structure of the parietal bone are traumatic in nature. In the vast majority of cases, the defect occurs precisely at the point where the force is applied. In this case, fractures of the parietal bone have several varieties:

• linear;
• depressed;
• splintered.

Linear fractures suggest the formation of a crack. This is usually preceded by serious compression of the skull from the outside. Depressed fractures are characterized by the presence of a part of the bone that is deflected into the cranial cavity. As for comminuted fractures, they involve the division of the parietal bone into several separate parts. In this case, usually only a certain area of ​​it suffers.

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1st temporal bone
2-parietal bone
3-crown (toothed) suture
4-frontal bone
5-frontal tubercle ( tuber frontale)
6-greater wing of the sphenoid bone ( ala major ossis sphenoidalis)
7-socket
8-tear bone ( os lacrimale)
9-nose bone ( os nasale)
10-frontal process of the maxilla ( processus frontalis maxillae)
11-upper jaw
12-alveolar eminences of the maxilla
13-zygomatic bone
14-mental foramen
15-tuberosity of the lower jaw
16-coronoid process of the mandible ( processus coronoideus mandibulae)
17-zygomatic arch ( arcus zygomaticus)
18-styloid process ( processus styloideus)
19-articular process of the mandible
20 mastoid process of the temporal bone ( processus mastoideus ossis temporalis)
21-external auditory canal ( meatus acusticus externus)
22 scales of the temporal bone
23-occipital bone
24-inferior temporal line
25-superior temporal line.

1st frontal bone
2-coronal stitch ( sutura coronalis)
3-parietal bone
4-socket
5-scales of the temporal bone
6-zygomatic bone
7-upper jaw
8-hole hole
9-lower jaw
10-mental puffiness
11 teeth of the lower jaw
12-intermaxillary suture
13-nasal bone ( os nasale)
14-zygomatic arch ( arcus zygomaticus)
15-tear bone ( os lacrimale)
16th large wing of the sphenoid bone ( ala major ossis sphenoidalis)
17-brow ridge
18-glabella (glabella)
19-frontal tubercle.

1-frontal scales ( squama frontalis)
2-frontal tubercle ( tuber frontale)
3-glabella (glabella)
4-zygomatic process ( processus zygomaticus)
5-supraorbital margin ( margo supraorbitalis)
6-nasal part (frontal bone)
7-nasal spine ( spina nasalis)
8-frontal notch
9-brow ridge
10-supraorbital foramen ( foramen supraorbitalis)
11-temporal line

1-parietal edge
2-sulcus of the superior sagittal sinus ( )
3-frontal ridge ( crista frontalis)
4-zygomatic process ( processus zygomaticus)
5-finger-shaped impressions ( impressions digitales)
6-blind hole ( foramen caecum)
7-nose ( pars nasalis)
8-orbital part ( pars orbitalis)
9-cerebral eminences
10-arterial grooves ( sulci arteriosi)
11-frontal scales.

1-visual channel ( canalis opticus)
2-back saddle
3-posterior oblique process
4-anterior oblique process
5-small wing ( ala minor)
6-superior orbital fissure ( fissura orbitalis superior)
7-parietal angle
8-large wing (cerebral surface)
9-round hole ( foramen rotundum)
10-pterygoid canal ( canalis pterygoideus)
11-scaphoid fossa
12-lateral plate (pterygoid process)
13-pterygoid notch ( incisura pterygoidea)
14-groove of the pterygoid hook
15-vaginal process
16-wedge ridge
17-body of the sphenoid bone ( corpus ossis sphenoidalis)
18-medial plate (pterygoid process)
19-wing hook ( Hamulus pterygoideas)
20-pterygoid fossa ( fossa pterygoidea)
21-sulcus of the internal carotid artery

1-aperture of the sphenoid sinus ( aperture sinus sphenoidalis)
2-back saddle
3-wedge shell ( conchae sphenoidalis)
4-small wing ( ala minor)
5-superior orbital fissure ( fissura orbitalis superior)
6-zygomatic margin
7-infratemporal surface, 8-sphenoid bone ( spina ossis sphenoidalis)
9-pterygopalatine groove
10-lateral plate ( lamina lateralis)
11-wing hook ( Hamulus pterygoideas)
12-medial plate of the pterygoid process
13-vaginal process
14-wedge comb
15-pterygoid notch ( incisura pterygoidea)
16-pterygoid canal ( canalis pterygoideus)
17-round hole ( foramen rotundum)
18-temporal crest ( crista infratemporalis)
19-orbital surface of the greater wing
20-temporal surface of the greater wing

1-sulcus of the superior sagittal sinus ( sulcus sinus sagittalis superioris)
2-squama of occipital bone
3-internal occipital protuberance ( )
4-internal nuchal crest ( crista occipitalis inferna)
5-foramen magnum ( foramen occipitale magnum)
6-sulcus of the sigmoid sinus ( sulcus sinus sigmoidei)
7-mouse channel
8-groove of the inferior petrosal sinus ( )
9-slope ( clivus)
10-basilar (main) part
11-lateral part ( pars lateralis)
12-Jegment Tenderloin
13th jugular tubercle
14-jugular process
15-inferior occipital fossa
16-sulcus of the transverse sinus ( sulcus sinus transversi)
17-superior occipital fossa

1-highest nuchal line
2-external occipital protuberance ( )
3-superior nuchal line ( linea nachalis superior)
4-inferior nuchal line ( linea nuchalis inferior)
5-condylar canal ( canalis condylaris)
6-occipital condyle ( condylus occipitalis)
7-intraspinal process
8-pharyngeal tubercle ( tuberculum phanryngeum)
9-basilar (main) part
10-lateral part ( pars lateralis)
11-jugular notch
12-jugular process
13th condylar fossa ( fossa condylaris)
14-foramen magnum ( foramen occipitale magnum)
15-neck surface (platform)
16-external nuchal crest ( crista occipitalis externa)
17-occipital scales

1-frontal angle ( angulus frontalis)
2-superior temporal line
3-frontal edge ( margo frontalis)
4-inferior temporal line
5-wedge angle ( angulus sphenoidalis)
6-scale edge
7-mastoid angle ( angulus mastoideum)
8-occipital edge ( margo occipitalis)
9-parietal tubercle ( tuber parietale)
10-sagittal edge

1-occipital angle ( angulus occipitalis)
2-occipital edge ( margo occipitalis)
3-arterial grooves ( sulci arteriosi)
4-sulcus of the sigmoid sinus ( sulcus sinus sigmoidei)
5-mastoid angle ( angulus mastoideum)
6-scale edge
7-wedge angle ( angulus sphenoidalis)
8-frontal edge ( margo frontalis)
9-frontal angle ( angulus frontalis)
10-pit granulations
11-sagittal edge
12-sulcus of the superior sagittal sinus.

1-cockscomb ( crista galli)
2-orbital plate ( lamina orbitalis)
3-perpendicular plate ( lamina perpendicularis)
4-uncinate process ( processus uncinatus)
5-middle turbinate ( concha nasalis media)
6-superior turbinate ( concha nasalis superior)
7-lattice cells.

1-perpendicular plate ( lamina perpendicularis)
2-middle turbinate ( concha nasalis media)
3-cockscomb ( crista galli)
4-lattice cells
5-grid plate
6-orbital plate ( lamina orbitalis)
7-anterior ethmoidal groove
8-uncinate process

1-squamous part (scales) of the temporal bone
2-zygomatic process ( processus zygomaticus)
3-articular tubercle ( tuberculum articulare)
4-mandibular fossa ( fossa mandibularis)
5-stony-scaly fissure ( fissure petrosquamosa)
6-petrostympanic (Glaserian) fissure
7-styloid process ( processus styloideus)
8-tympanic part of the temporal bone
9-external auditory opening ( porus acusticus externus)
10-mastoid process ( processus mamillaris)
11-mastoid notch ( incisura mastoidea)
12-tympanomastoid fissure ( fissura tympanomastoidea)
13-supragastric spine (above the auditory canal)
14-mastoid foramen ( foramen mastoideus)
15-parietal notch ( incisura parietalis)
16-temporal line.

1-squamosal part of the temporal bone
2-arc-shaped elevation ( eminentia arcuata)
3-parietal notch ( incisura parietalis)
4-roof drum cavity
5-sulcus of the superior petrosal sinus
6-boroeda of the sigmoid sinus
7-mastoid foramen ( foramen mastoideus)
8-occipital edge ( margo occipitalis)
9-external opening (aperture) of the vestibule water supply
10-subarc fossa ( fossa subarcuata)
11-vagina of the styloid process ( vagina processus styloidei)
12-styloid process ( processus styloideus)
13-external opening (aperture) of the cochlear canaliculus
14-internal auditory opening ( porus acusticus internus)
15-groove of the inferior petrosal sinus ( )
16-posterior surface of the pyramid of the temporal bone
17-top of the pyramid
18 zygomatic process ( processus zygomaticus)
19-arterial grooves

1-external auditory canal ( meatus acusticus externus)
2-styloid process ( processus styloideus)
3-pose-disarticular tubercle
4-mandibular fossa ( fossa mandibularis)
5-articular tubercle ( tuberculum articulare)
6-zygomatic process ( processus zygomaticus)
7-stony-scaly shel
8-lower process of the pyramid of the temporal bone (roof of the tympanic cavity)
9-petrostympanic (Glaser's) fissure
10-musculotubal canal ( canalis muculotubarius)
11-internal opening of the carotid canal ( foramen caroticum internum)
12-external opening of the carotid canal ( foramen caroticum externum)
13-petalled dimple ( fossula petrosa)
14-external opening (aperture) of the cochlear canaliculus
15 mastoid tubule
16-jugular fossa
17-stylomastoid foramen ( foramen mastoideus)
18-occipital edge ( margo occipitalis)
19-sulcus of the occipital artery ( sulcus arteriae occipitalis)
20-mastoid notch ( incisura mastoidea)
21st mastoid process ( processus mamillaris)

1-temporal bone scales
2-mastoid cave ( antrum mastoideum)
3-prominence of the lateral semicircular canal
4-protrusion of the facial nerve canal
5-window vestibule
6-probe in the facial nerve canal
7-cleft canal of the greater petrosal nerve ( hiatus canalis nervi petrosi majoris)
8-cleft canal of the lesser petrosal nerve ( hiatus canalis nervi petrosi minoris)
9-sulcus of the greater petrosal nerve ( sulcus nervi petrosi majoris)
10-sulcus of the lesser petrosal nerve ( sulcus nervi petrosi minoris)
11-hemicanal of the tensor tympani muscle
12-half-channel auditory tube
13-internal opening of the carotid canal
14-external opening of the carotid canal ( foramen caroticum externum)
15-Cape
16-tympanic cavity
17-pyramid elevation
18-stylomastoid foramen ( foramen mastoideus)
19 mastoid cells

1-frontal process
2-anterior lacrimal ridge
3-infraorbital margin
4-front surface
5-infraorbital foramen
6-nose tenderloin
7-anterior nasal spine
8-body of the upper jaw ( corpus maxillae)
9-alveolar eminences
10-zygomatic process ( processus zygomaticus)
11-alveolar foramina
12-tubercle of the upper jaw ( tuber maxillae)
13-infraorbital groove
14-orbital surface

1-frontal process
2-tear edge
3-tear groove
4-maxillary (Maxillary) sinus
5-nasal surface of the body of the maxilla
6-greater palatine sulcus
7-alveolar process
8-palatine process
9-incisal canal ( canalis incisivus)
10-anterior nasal spine
11-shell comb
12 lattice comb.

1-frontal process
2-orbital surface ( facies orbitalis)
3-zygomatic-orbital foramen
4-lateral surface
5-temporal process

1-grid edge
2nd left wing of the opener
3-free edge
4-palatal margin

1-internasal suture
2-hole of the nasal bone
3-free edge

1-lacrimal process
2-ethmoid process
3-bottom (free) edge

1-tear groove
2-posterior lacrimal ridge
3-tear hook

1st orbital process
2-latticed comb
3-sphenopalatine notch
4-sphenoid process
5-perpendicular plate (nasal surface)
6-shell comb
7-horizontal plate
8-pyramidal process
9-greater palatine sulcus
10-posterior nasal spine
11-nasal comb
12-maxillary process

1-coronoid process ( processus coronoideus)
2-condylar process
3-hole of the lower jaw ( foramen mandibulae)
4-notch of the lower jaw ( incisura mandibulae)
5-head of the lower jaw ( caput mandibulae)
6th branch of the lower jaw ( ramus mandibulae)
7-chewing bulkiness
8-angle of the lower jaw ( angulus mandibulae)
9-oblique line
10-base of the lower jaw
11-body of the lower jaw ( corpus mandibulae)
12-mental foramen
13-mental protuberance
14-alveolar eminences

1-body of the hyoid bone ( corpus ossis hyoidei)
2-big horn
3-small horn

1-palatine process of the maxilla ( processus palatinus maxillae)
2-incisal hole
3-median palatal suture
4-transverse palatal suture
5-choana
6-inferior orbital fissure ( fissura orbitalis inferior)
7-zygomatic arch ( arcus zygomaticus)
8-wing opener
9-pterygoid fossa ( fossa pterygoidea)
10-lateral plate of the pterygoid process
11-pterygoid process ( processus pterygoideus)
12-oval hole ( foramen ovale)
13-mandibular fossa
14-styloid process ( processus styloideus)
15-external auditory canal ( meatus acusticus externus)
16 mastoid process ( processus mamillaris)
17-mastoid notch ( incisura mastoidea)
18-occipital condyle ( condylus occipitalis)
19th condylar fossa ( fossa condylaris)
20-major (occipital) foramen
21-inferior nuchal line ( linea nuchalis inferior)
22-external occipital protuberance ( protuberantia occipitalis externa)
23-pharyngeal tubercle ( tuberculum phanryngeum)
24-muscular channel
25 jugular hole
26-occipitalomastoid suture
27-external carotid foramen
28-stylomastoid foramen ( foramen mastoideus)
29-ragged hole
30-petrostympanic fissure ( fissura petrotympanica)
31st spinous foramen ( foramen spinosum)
32-articular tubercle ( tuberculum articulare)
33-wedge-squamous suture
34-wing hook ( Hamulus pterygoideas)
35-greater palatine foramen
36-zygomatic-maxillary suture

1st orbital part of the frontal bone
2-cock feb
3-grid plate
4-view channel ( canalis opticus)
5-pituitary fossa
6-back saddle. 7-round hole ( foramen rotundum)
8-oval hole ( foramen ovale)
9-ragged hole
foramen tenspinalis ( foramen spinosum)
11-internal auditory opening ( porus acusticus internus)
12 jugular foramen
13-hyoid canal
14-lambdoid suture ( sutura lamboidea)
15-slope ( clivus)
16-beard of the transverse sinus
17-internal occipital protrusion
18-major (occipital) foramen
19-occipital scales ( squama occipitalis)
20-sulcus of the sigmoid sinus ( sulcus sinus sigmoidei)
21-pyramid (petrous part) of the temporal bone
22-squamosal part of the temporal bone
23-greater wing of the sphenoid bone ( ala major ossis sphenoidalis)
24-lesser wing of the sphenoid bone

1st zygomatic process of the frontal bone ( processus zygomaticus ossis frontalis)
2nd large wing of the sphenoid bone (orbital surface)
3-orbital surface of the zygomatic bone
4-frontal process of the zygomatic bone
5-inferior orbital fissure ( fissura orbitalis inferior)
6-zygomatico-facial deviation
7-zygomatic bone
8-infraorbital groove
9-upper jaw (maxillary bone, infraorbital surface)
10-infraorbital foramen
11-orbital surface of the maxilla ( facies orbitalis maxillae)
12-nasal cavity
13-orbital process of the palatine bone
14-tear bone ( os lacrimale)
15-orbital plate of the ethmoid bone
16-nasal bone ( os nasale)
17-tear groove (tear bone)
18-posterior lacrimal fene (lacrimal bone)
19-frontal process of the maxilla ( processus frontalis maxillae)
20-anterior ethmoidal opening
21-posterior ethmoidal foramen
22 frontal notch
23-orbital part (orbital surface) of the frontal bone
24-supraorbital foramen ( foramen supraorbitalis)
25-view channel ( canalis opticus)
26-lesser wing of the sphenoid bone ( ala minor ossis sphenoidalis)
27-superior orbital fissure

1-frontal bone (scales of the frontal bone)
2-frontal sinus
3-cockscomb ( crista galli)
4-ethmoid plate of ethmoid bone
5-superior turbinate ( concha nasalis superior)
6-middle turbinate ( concha nasalis media)
7-sphenoid sinus ( sinus sphenoidalis)
8-sphenopalatine foramen
9-inferior nasal concha ( concha nasalis inferior)
10-vertical plate of the palatine bone
11-medial plate of the pterygoid process
12-horizontal plate of the palatine bone
13-palatine process of the maxilla ( processus palatinus maxillae)
14-incisal canal ( canalis incisivus)
15-inferior nasal passage ( meatus nasi inferior)
16-medium nasal passage ( meatus nasi medius)
17-superior nasal passage ( meatus nasi superior)
18-nose bone.

1-coronal suture ( sutura coronalis)
2-sagittal suture ( sutura sagittalis)
3-lambdoid suture ( sutura lamboidea)
4-occipital bone (squama)
5-parietal bone
6-frontal bone

1st frontal bone
2-frontal ridge ( crista frontalis)
3-pit granulations
4-crown stitch ( sutura coronalis)
5-arterial grooves ( sulci arteriosi)
6-parietal bone
7-sulcus of the superior sagittal sinus ( sulcus sinus sagittalis superioris)
8-occipital bone

1-frontal seam
2-frontal tubercle ( tuber frontale)
3-anterior (frontal) fontanel
4-crown stitch ( sutura coronalis)
5-parietal tubercle ( tuber parietale)
6-sagittal suture
7-posterior occipital) fontanelle
8-occipital bone
9-lambdoid suture

1st frontal bone
2-anterior (frontal) fontanel
3-crown seam ( sutura coronalis)
4-parietal tubercle ( tuber parietale)
5-posterior (occipital) fontanel
6-occipital bone (squama)
7-mastoid fontanelle
8-petallous part (pyramid) of the temporal bone
9-temporal bone scales
10-tympanic bone (tympanic ring)
11-wedge-shaped (anterolateral) fontanelle
12-mandible
13-zygomatic bone
14-upper jaw
15-socket

1-roof (vault) of the skull
2-frontal bone
3-frontal sinus
4-cells of the ethmoid bone
5-bone septum of the nasal cavity
6-anterior nasal spine
7-intermaxillary suture
8-lower jaw
9-mental protuberance
10-nasal cavity
11-maxillary sinus
12 mastoid process ( processus mamillaris)
13-socket

Scull, cranium, - consists of two sections - the bones of the skull, ossa cranium, and facial bones, ossa faciei.

The skeleton of the head is the skull, cranium, the individual bones of which are subdivided into the bones of the medulla of the skull, which form the cranial cavity, cavitas cranii, receptacle for the brain and facial bones, ossa faciei. The skull serves as a container for the brain (cerebral cranium) and some sensory organs (sight, hearing and smell).

The bones of the face (facial part of the skull) make up the skeleton of the face, the initial parts of the digestive and respiratory systems.

Both sections of the skull are formed from separate bones, fixedly connected to each other using sutures, suturae, and cartilaginous joints, synchondroses, with the exception of the lower jaw, which is movably connected to the skull through the temporomandibular joint, .

Based on data on its development, the bones of the brain skull include unpaired bones: occipital, sphenoid, frontal, ethmoid, vomer - and paired bones: temporal, parietal, inferior turbinate, lacrimal, nasal.

The bones of the face include paired bones: the upper jaw, palatine bone, zygomatic bone - and unpaired bones: the lower jaw and hyoid bone. The latter, although located in the neck, develops as a bone of the facial part of the skull and is described together with it.

Topographically, the inferior turbinate, vomer, lacrimal and nasal bones belong to the facial skeleton.

Occipital bone

Occipital bone, os occipitale, unpaired, forms the posteroinferior part of the skull. Its outer surface is convex, and its inner, cerebral, concave surface. In its anterior-inferior section there is a large (occipital) foramen, foramen magnum, connecting the cranial cavity with the spinal canal. This opening is surrounded by a shallow groove of the occipital sinus, sulcus sinus occipitalis. Based on data on the process of development of the occipital bone, four parts are distinguished in it surrounding the large (occipital) foramen: the basilar part - in front of the large (occipital) foramen, paired lateral parts - on the sides of it, and the occipital scales, located behind.

basilar part, pars basilaris, short, thick, quadrangular; its posterior edge is free, smooth and slightly pointed, limiting the foramen magnum (occipital) in front; the anterior edge is thickened and rough, connected to the body of the sphenoid bone through cartilage, forming sphenoid-occipital synchondrosis, synchondrosis sphenooccipitalis.

During adolescence, cartilage is replaced by bone tissue and both bones merge into one. The upper surface of the basilar part, facing the cranial cavity, is smooth and slightly concave. It forms a slope with the part of the body of the sphenoid bone located in front of it, clivus, directed to the large (occipital) foramen (on it lie the medulla oblongata, the bridge and the basilar artery of the brain with branches). In the middle of the lower, outer, slightly convex surface of the basilar part there is a small pharyngeal tubercle, tuberculum pharyngeum, (the place of attachment of the anterior longitudinal ligament and the fibrous membrane of the pharynx), and rough lines (traces of attachment of the rectus anterior and long muscles of the head).

The outer, slightly irregular edge of the basilar part and lateral parts of the occipital bone is adjacent to the posterior edge of the petrous part of the temporal bone. A petrosoccipital fissure is formed between them, fissura petrooccipitalis, on a non-macerated skull it is made of cartilage, forming the petrooccipital synchondrosis, synchondrosis petrooccipitalis, which, as a remnant of the cartilaginous skull, ossifies with age.

Lateral parts paries laterales, somewhat elongated, thickened in the posterior sections, and somewhat narrowed in the anterior; they form the lateral sides of the large (occipital) foramen, fused in front with the basilar part, and behind with the occipital scales.

On the cerebral surface of the lateral part, at its outer edge, there is a narrow groove of the inferior petrosal sinus, sulcus sinus petrosi inferioris, which is adjacent to the posterior edge of the petrous part of the temporal bone, forming, with the groove of the same name in the temporal bone, a canal where the venous inferior petrosal sinus lies, sinus petrosus inferior.

On the lower, outer surface of each lateral part there is an oblong-oval convex articular process - the occipital condyle, condylus occipitalis. Their articular surfaces come closer in front and diverge behind; they articulate with the superior articular fossa of the atlas. Behind the occipital condyle there is a condylar fossa, fossa condylaris, and at its bottom there is a hole leading into the unstable condylar canal, canalis condylaris, which is the location of the condylar emissary vein, v. emissaria condylaris.

On the outer edge of the lateral part there is a large, smooth-edged jugular notch, incisura jugularis, on which a small intrajugular process protrudes, processus intrajugularis.

The jugular notch with the same fossa of the petrous part of the temporal bone forms the jugular foramen, foramen jugulare.

The intrajugular processes of both bones divide this opening into two parts: the large posterior one, in which the superior bulb of the internal jugular vein lies, bulbus v. jugularis superior, and the smaller anterior one, through which the cranial nerves pass: glossopharyngeal ( n. glossopharyngeus), wandering ( n. vagus) and additional ( n. accessorius).

Posteriorly and externally, the jugular notch is limited by the jugular process, processus jugularis. On the outer surface of its base there is a small paramastoid process, processus paramastoideus, (place of attachment of the rectus lateral capitis muscle, m. rectus capitis lateralis).

Behind the jugular process, on the side of the inner surface of the skull, there is a wide groove of the sigmoid sinus, sulcus sinus sigmoidei, which is a continuation of the groove of the same name in the temporal bone. Anterior and medial lies the smooth jugular tubercle, tuberculum jugular. Posteriorly and downward from the jugular tubercle, between the jugular process and the occipital condyle, the hypoglossal canal passes through the bone, canalis hypoglossalis, (it contains the hypoglossal nerve, n. hypoglossus).

occipital scales, squama occipitalis, limits the posterior foramen magnum (occipital) and makes up most of the occipital bone. This is a wide, curved, triangular plate with a concave inner (cerebral) surface and a convex outer surface.

The lateral edge of the scales is divided into two sections: a larger upper, highly serrated lambdoid edge, margo lamboideus, which, joining the occipital edge of the parietal bones, forms a lambdoid suture, sutura lamboidea, and a smaller lower, slightly serrated mastoid margin, margo mastoideus, which, adjacent to the edge of the mastoid process of the temporal bone, forms the occipital-mastoid suture, sutura occipitomastoidea.

In the middle of the outer surface of the scales, in the area of ​​its greatest convexity, there is an external occipital protrusion, protuberantia occipitalis externa, easily palpable through the skin. Paired convex upper nuchal lines diverge from it, lineae nuchae superiores, above which and parallel to them there are additional highest nuchal lines, lineae nuchae supremae.

The external occipital crest descends from the external occipital protuberance to the foramen magnum (foramen magnum), crista occipitalis externa. At the middle of the distance between the large (occipital) foramen and the external occipital protrusion, the lower nuchal lines diverge from the middle of this ridge to the edges of the occipital scales, lineae nuchae inferiores, running parallel to the top. All these lines are places of muscle attachment. On the surface of the occipital scales below the upper nuchal lines, muscles ending on the occipital bone are attached.

On the surface of the brain facies cerebralis, the occipital scales have a cruciform eminence, eminentia cruciformis, in the middle of which the internal occipital protrusion rises ( protuberantia occipitalis interna). On the outer surface of the scales it corresponds to the external occipital protrusion.

The groove of the transverse sinus extends from the cruciate eminence in both directions, sulcus sinus transversi, upward – groove of the superior sagittal sinus, sulcus sinus sagittalis superioris, downwards – internal occipital crest, crista occipitalis interna, going to the posterior semicircle of the large (occipital) foramen. The dura mater with the venous sinuses located in it is attached to the edges of the grooves and to the internal occipital crest; in the region of the cruciate eminence there is a confluence of these sinuses.

Sphenoid bone

Sphenoid bone, os sphenoidale, unpaired, forms the central section of the base of the skull.

The middle part of the sphenoid bone is the body, corpus, cubic in shape, has six surfaces. On the upper surface, facing the cranial cavity, there is a depression - the sella turcica, sella turcica, in the center of which is the pituitary fossa, fossa hypophysialis. It contains the pituitary gland, hypophysis. The size of the pit depends on the size of the pituitary gland. The border of the sella turcica in front is the tubercle of the sella, tuberculum sellae. Posterior to it, on the lateral surface of the saddle, there is a non-constant middle inclined process, processus clinoideus medius.

Anterior to the tubercle sella there runs a shallow transverse precross groove, sulcus prechiasmatis. Behind it lies the optic chiasm, chiasma opticum. Laterally, the groove passes into the optic canal, canalis opticus. In front of the furrow there is a smooth surface - a wedge-shaped eminence, jugum sphenoidale, connecting the small wings of the sphenoid bone. The anterior crane of the upper surface of the body is serrated, protrudes slightly forward and connects with the posterior edge of the ethmoidal plate of the ethmoid bone, forming a sphenoethmoidal suture, sutura spheno-ethmoidalis. The posterior border of the sella turcica is the dorsum of the sella, dorsum sellae, which ends on the right and left with a small posterior inclined process, processus clinoideus posterior.

A carotid groove runs along the sides of the saddle from back to front, sulcus caroticus, (trace of the internal carotid artery and the accompanying nerve plexus). At the posterior edge of the groove, on its outer side, a pointed process protrudes - a wedge-shaped tongue, lingula sphenoidalis.

The posterior surface of the dorsum sella passes into the upper surface of the basilar part of the occipital bone, forming a slope, clivus, (on it lie the bridge, medulla oblongata, basilar artery and its branches). The posterior surface of the body is rough; through a cartilaginous layer it connects to the anterior surface of the basilar part of the occipital bone and forms sphenoid-occipital synchondrosis, synchondrosis spheno-occipitalis. As we age, the cartilage is replaced by bone tissue and the two bones fuse together.

The front surface of the body and part of the bottom face the nasal cavity. A wedge-shaped ridge protrudes in the middle of the front surface, crista sphenoidalis, its anterior edge is adjacent to the perpendicular plate of the ethmoid bone. The lower process of the crest is pointed, extended downwards and forms a wedge-shaped beak, rostrum sphenoidale. The latter is connected to the wings of the opener, alae vomeris, forming the vomerococoid canal, canalis vomerorostratis, lying along the midline between the upper edge of the vomer and the wedge-shaped beak. Lateral to the ridge lie thin curved plates - wedge-shaped shells, conchae sphenoidales. The shells form the anterior and partly the lower walls of the sphenoid sinus, sinus sphenoidalis. Each shell has a small opening - the aperture of the sphenoid sinus, apertura sinus sphenoidalis. Outside the aperture there are small depressions that cover the cells of the posterior part of the labyrinth of the ethmoid bone. The outer edges of these recesses are partially connected to the orbital plate of the ethmoid bone, forming a sphenoethmoidal suture, sutura spheno-ethmoidalis, a lower - with orbital processes, processus orbitalis, palatine bone.

sphenoid sinus, sinus sphenoidalis– a paired cavity that occupies most of the body of the sphenoid bone; it belongs to the air-bearing paranasal sinuses. The right and left sinuses are separated from one another by the septum of the sphenoid sinuses, septum sinuum sphenoidalium, which anteriorly continues into the wedge-shaped ridge. As in the frontal sinuses, the septum is often asymmetrical, as a result of which the size of the sinuses may not be the same. Through the aperture of the sphenoid sinus, each sphenoid sinus communicates with the nasal cavity. The cavity of the sphenoid sinus is lined with mucous membrane.

Small wings, alae minores, the sphenoid bones extend in both directions from the anterosuperior corners of the body in the form of two horizontal plates, at the base of which there is a rounded hole. From this hole begins a bone canal up to 5-6 mm long - the optic canal, canalis opticus. It contains the optic nerve, n. opticus, and ophthalmic artery, a. ophthalmica. The small wings have an upper surface facing the cranial cavity and a lower surface directed into the orbital cavity and closing the superior orbital fissure from above, fissura orbitalis superior.

The anterior edge of the lesser wing, thickened and jagged, connects to the orbital part of the frontal bone. The posterior edge, concave and smooth, protrudes freely into the cranial cavity and is the boundary between the anterior and middle cranial fossae, fossae cranii anterior et media. The medial posterior edge ends in a prominent, well-defined anterior inclined process, processus clinoideus anterior, (a part of the dura mater is attached to it - the diaphragm of the sella turcica, diaphragma sellae).

Big wings, alae majores, extend from the lateral surfaces of the body of the sphenoid bone and are directed outward.

The large wing has five surfaces and three edges.

facies cerebralis, concave, facing the cranial cavity. It forms the anterior section of the middle cranial fossa. There are finger-shaped impressions on it, impressiones digitatae, [gyrorum]), and arterial grooves, sulci arteriosi, (relief imprints of the adjacent surface of the brain and middle meningeal arteries).

At the base of the wing there are three permanent openings: a round opening is located inwardly and anteriorly, foramen rotundum, (the maxillary nerve exits through it, n maxillaris), outward and posterior to the round is the foramen ovale, foramen ovale, (it passes the mandibular nerve, n. mandibularis), and outward and posterior to the oval - the spinous foramen, foramen spinosum, (the middle meningeal artery, vein and nerve come through it). In addition, in this area there are intermittent holes. One of them is the venous opening, foramen venosum, located slightly posterior to the foramen ovale. It passes the vein coming from the cavernous sinus into the pterygoid venous plexus. The second is a rocky hole, foramen petrosum, through which the lesser petrosal nerve passes, is located behind the spinous foramen, closer to the axis of the sphenoid bone.

Anterior superior orbital surface, facies orbitalis, smooth, diamond-shaped, facing the cavity of the orbit and forms most of its outer wall. The lower edge of the surface is spaced from the posterior edge of the orbital surface of the body of the upper jaw - the lower orbital fissure is formed here, fissura orbitalis inferior.

Anterior maxillary surface, facies maxillaris, - a small triangular area, limited above by the orbital surface, on the side and below by the root of the pterygoid process of the sphenoid bone. It is part of the posterior wall of the pterygopalatine fossa, fossa pterygopalatina, it has a round hole.

Superolateral temporal surface, facies temporalis, somewhat concave, takes part in the formation of the wall of the temporal fossa, fossa temporalis, (bundles of the temporal muscle begin from it). This surface is limited below by the infratemporal crest, crista infratemporal, below the ridge there is a surface on which the oval and spinous foramina open. It forms the superior wall of the infratemporal fossa ( fossa infratemporalis), (part of the lateral pterygoid muscle begins here ( m. pterygoideus lateralis).

superior frontal margin, margo frontalis, widely serrated, connects to the orbital part of the frontal bone, forming a sphenoid-frontal suture, sutura sphenofrontalis. The outer sections of the frontal edge end with a sharp parietal edge, margo parietalis, which with the wedge-shaped angle of the other bone forms the sphenoid-parietal suture, sutura sphenoparietalis. The internal sections of the frontal edge pass into a thin free edge, which is spaced from the lower surface of the lesser wing, limiting the superior orbital fissure from below.

Anterior zygomatic margin, margo zygomaticus, jagged frontal process, processus frontalis, the zygomatic bone and the zygomatic margin are connected to form the sphenoid-zygomatic suture, sutura sphenozygomatica.

Posterior scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, temporal bone and forms a sphenoid-squamous suture, sutura sphenosquamosa. Posteriorly and outwardly, the scaly edge ends with the spine of the sphenoid bone (the place of attachment of the sphenomandibular ligament, lig sphenomandibularis, and bundles of the muscle that strains the velum palatine, m. tensor veli palatini).

Inward to the spine of the sphenoid bone, the posterior edge of the greater wing lies in front of the petrous part, pars petrosa, temporal bone and limits the sphenoid-petrosal fissure, fissura sphenopetrosa, passing medially into the foramen lacerum, foramen la-lacerum, on a non-macerated skull this gap is filled with cartilaginous tissue and forms a wedge-shaped petrosal synchondrosis, synchondrosis sphenopetrosa.

Pterygoid processes ( processus pterygoidei, extend from the junction of the large wings with the body of the sphenoid bone and are directed downwards. They are formed by two plates - lateral and medial. Lateral plate, lamina lateralis, (processus pterygoidei), wider, thinner and shorter than the medial one (the lateral pterygoid muscle begins from its outer surface, ( m. pterygoideus lateralis). medial plate, lamina medialis, (processus pterygoidei), narrower, thicker and slightly longer than the lateral one. Both plates grow together with their anterior edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea, (the medial pterygoid muscle begins here, m. pterygoideus medialis). In the lower parts, both plates do not fuse and limit the pterygoid notch, incisura pterygoidea. It contains a pyramidal process, processus pyramidalis, palatine bone. The free end of the medial plate ends with a wing-shaped hook directed downwards and outwards, hamulus pterygoideus, on the outer surface of which there is a groove of the pterygoid hook, sulcus hamuli pterygoidei, (the tendon of the muscle that strains the velum palatine is thrown through it, m. tensor veli palatini).

The posterosuperior edge of the medial plate at the base expands and forms a scaphoid fossa, fossa scaphoidea.

Outward from the navicular fossa there is a shallow groove of the auditory tube, sulcus tubae auditivae, which laterally passes to the lower surface of the posterior edge of the large wing and reaches the spine of the sphenoid bone (the cartilaginous part of the auditory tube is adjacent to this groove). Above the scaphoid fossa and medially there is an opening where the pterygoid canal begins, canalis pterygoideus, (vessels and nerves pass through it). The canal runs in the sagittal direction in the thickness of the base of the pterygoid process and opens on the maxillary surface of the greater wing, on the posterior wall of the pterygopalatine fossa.

The medial plate at its base passes into the inwardly directed flat, horizontally running vaginal process, processus vaginalis, which is located under the body of the sphenoid bone, covering the side of the vomer wing, ala vomeris. In this case, the groove of the vaginal process facing the wing of the vomer is the vomerovaginal groove, sulcus vomerovaginalis, turns into the vomerovaginal canal, canalis vomerovaginalis.

Outward from the process there is a small sagittal sulcus running sagittally, sulcus palatovaginalis. Adjacent below is the sphenoid process of the palatine bone, processus sphenoidalis ossis palatini, closes the groove into the canal of the same name, canalis palatovaginalis, (in the vomerovaginal and palatovaginal canals the nerve branches of the pterygopalatine ganglion pass, and in the palatovaginal canal, in addition, branches of the sphenopalatine artery).

Sometimes the pterygospinous process is directed from the posterior edge of the outer plate towards the spine of the sphenoid bone, processus pterygospinosus, which can reach the specified spine and form a hole.

The anterior surface of the pterygoid process connects with the posterior surface of the upper jaw in the region of the medial edge of the tubercle, forming the sphenoid-maxillary suture, sutura sphenomaxillaris, which lies deep in the pterygopalatine fossa.

Frontal bone

frontal bone, os frontale, in an adult, forms the anterior part of the cranial vault and partly its base. It consists of four parts: the frontal scales, two orbital parts and the nasal part.
Frontal scales

Frontal scales, squama frontalis, convex anteriorly, has the following surfaces: the outer, or frontal, two temporal, or lateral, and the inner, or cerebral.

Outside surface, facies externa, smooth, convex anteriorly. There is not always a noticeable elevation along the midline - the metopic suture, sutura metopica) - a trace of fusion of the halves of the frontal bone that existed in early childhood. In the anterior sections, the frontal surface of the scales passes into the orbital surface, facies orbitalis, forming a supraorbital edge on each side, margo supraorbitalis, which is the upper part of the orbital margin, margo orbitalis. Above and parallel to the supraorbital margin, an arched elevation protrudes more or less prominently - the brow ridge, arcus superciliaris. Above each brow ridge, a rounded elevation is visible - the frontal tubercle, tuber frontale. Between the convexities of the superciliary arches and slightly above them, the surface of the frontal scales in the region of the glabella looks like a somewhat recessed area - this is the glabella, glabella. At the inner third of the supraorbital margin there is a small supraorbital notch, incisura supraorbitalis. This notch is very variable and can be expressed in the form of a supraorbital foramen, foramen supraorbitale. Closer to the midline, i.e. more medially, lies an equally pronounced frontal notch, incisura frontalis, (the lateral branch of the supraorbital nerve and vessels pass through the supraorbital notch, and the medial branch of the same nerve and vessels pass through the frontal notch). A frontal opening may form at the site of this notch, foramen frontale.

Laterally, the supraorbital margin passes into a blunt, triangular-shaped zygomatic process, processus zygomaticus, its serrated edge connects with the frontal process of the zygomatic bone, forming the frontozygomatic suture, sutura frontozygomatica.

From the zygomatic process upward and backward, the temporal line is directed in an arcuate manner, linea temporalis, it separates the frontal surface of the scales from the temporal surface. Temporal surface, facies temporalis, is the anterior superior part of the temporal fossa, fossa temporalis, where the anterior bundles of the temporal muscle begin.

Inner surface, facies interna, concave. It has faint finger-like impressions ( impressiones digitatae, and unstable arterial grooves, sulci arteriosi, (as an imprint of the relief of the brain and blood vessels adjacent here).

In the middle of the inner surface of the frontal scales there is a groove of the superior sagittal sinus, sulcus sinus sagittalis superioris. Its both edges, heading upward and backward, pass into the groove of the same name in the parietal bones, and below they connect into a sharp frontal ridge, crista frontalis, (a process of the dura mater is attached to it - the falx cerebri). The lowest part of the crest and wing of the cockscomb of the ethmoid bone, ala cristae galli ossis ethmoidalis, form a channel - a blind hole, foramen cecum, in which there is a vein that drains blood from the nasal cavity to the superior sagittal sinus.

The upper, or posterior, edge of the frontal scales is the parietal edge, margo parietalis, thickened; its serrated edge connects with the frontal edge of the parietal bones, forming the coronal suture, sutura coronalis. The lower parts of the scales are triangular in shape, connected to the frontal edge of the large wings of the sphenoid bone.

Each orbital part pars orbitalis, the frontal bone is part of the upper wall of the orbit. From the supraorbital edge of the frontal scales it is directed backward and horizontally. It distinguishes between the inferior orbital and superior cerebral surfaces.

orbital surface, facies orbitalis, facing the cavity of the orbit, smooth and concave. In its lateral section, at the base of the zygomatic process, lies a shallow fossa of the lacrimal gland, fossa glandulae lacrimalis, – location of the lacrimal gland.

In the medial part of the orbital surface there is a weakly defined trochlear fossa, fovea trochlearis, near which there is often a cartilaginous trochlear spine, spina trochlearis, (a cartilaginous ring is attached here, which is a block of the tendon of the superior oblique muscle of the eyeball).

Superior cerebral surface facies cerebratis, the orbital part has well-defined imprints of the adjacent surface of the frontal lobes of the brain in the form of finger-like impressions, impressiones digitatae, gyrorum).

Orbital parts

The orbital parts are separated from each other by the ethmoidal notch, incisura ethmoidalis, in which the cribriform plate is located, lamina cribrosa, ethmoid bone. The notch on the sides is limited by an edge, outward from which there are dimples covering the open cells of the upper part of the labyrinth of the ethmoid bone, forming their upper wall. Between the ethmoid dimples there are two grooves running in the transverse direction - anterior and posterior, which, together with the same grooves of the labyrinth of the ethmoid bone, form the tubules. The latter open on the inner wall of the orbit - two small openings: the anterior ethmoidal foramen, foramen ethmoidae anterius,(the anterior ethmoidal vessels and nerve pass through it), and the posterior ethmoidal foramen, foramen ethmoidae posterius, (the posterior ethmoidal vessels and nerve pass through it). The edge of the ethmoidal notch is connected to the upper edge of the orbital plate, lamina orbitalis, ethmoid bone, forming the frontoethmoidal suture, sutura frontoethmoidalis, and in front - with the lacrimal bone - the frontolacrimal suture, sutura frontolacrimalis.

The posterior edge of the orbital part, racemed and serrated, connects with the small wing of the sphenoid bone, forming the internal portion of the sphenoid-frontal suture, sutura sphenofrontalis.

The lateral edge of the orbital part is rough and triangular in shape. It connects to the frontal edge of the greater wing of the sphenoid bone and forms the outer portion of the sphenoid-frontal suture.

Bow

bow part, pars nasalis, the frontal bone in the form of an arch closes the ethmoid notch in front. In front, in the middle of the nasal part, the nasal spine protrudes (sometimes double) obliquely downward and forward ( spina nasalis, pointed at the end and flattened on the sides. It is surrounded in front and on the side by a jagged nasal edge, margo nasalis. It connects to the upper edge of the nasal bone, forming the frontonasal suture, sutura frontonasalis, and with the frontal process ( processus frontalis) of the upper jaw, forming the frontomaxillary suture, sutura frontomaxillaris. The lower surface of the posterior parts of the nasal part has shallow dimples, which, as noted, cover the cells of the labyrinths of the ethmoid bone, which are open to the top.

On each side of the nasal spine there is one aperture of the frontal sinus, apertura sinus frontalis; heading upward and anteriorly, it leads into the cavity of the corresponding frontal sinus.

Frontal sinus, sinus frontalis, is a paired cavity lying between both plates of the frontal bone in its antero-inferior sections. Frontal sinus Refers to the air-bearing bones of the sinuses. The right sinus is separated from the left by the vertical septum of the frontal sinuses, septum sinuum frontalium. By deviating to the side, the septum causes the unequal size of the cavities of both sinuses. The boundaries vary dramatically. Sometimes the frontal sinuses reach upward to the frontal tuberosities, downward to the supraorbital margins, posteriorly to the lesser wings of the sphenoid bone, and laterally to the zygomatic processes. The frontal sinus aperture connects the frontal sinus and the middle meatus, meatus nasi medius, nasal cavity. The sinus cavity is lined with mucous membrane.

Ethmoid bone

Ethmoid bone, os ethmoidae, unpaired. Most of it lies in the upper parts of the nasal cavity, the smaller part lies in the anterior parts of the base of the skull. It has the shape of an irregular cube, consists of air cells and belongs to the group of air bones, ossa pneumatica.

In the ethmoid bone, there is a ethmoidal plate that runs horizontally, a perpendicular plate that lies vertically, and ethmoidal labyrinths located on both sides of the latter.

cribriform plate, lamina cribrosa, is the upper wall of the nasal cavity, located horizontally in the ethmoidal notch of the frontal bone, forming the frontoethmoidal suture, sutura frontoethmoidalis. It is perforated with 30-40 small holes, foramina fibrosae, through which nerves (olfactory nerve fibers) and vessels pass.

Perpendicular plate, lamina perpendicularis, is divided into two parts: a smaller upper one, lying above the cribriform plate, and a larger lower one, located under this plate. The upper part forms the cock's comb, crista galli, and is directed into the cranial cavity (the falx cerebri, a process of the dura mater, is attached to the crest).

The border of the anterior-inferior edge of the cockscomb on each lateral side is a non-permanent formation - the wing of the cockscomb, ala cristae galli. Both processes delimit the foramen cecum posteriorly and superiorly, foramen cecum, frontal bone. The lower part of the perpendicular plate is irregularly quadrangular in shape, directed vertically down into the nasal cavity, and forms the anterosuperior part of the bony septum. From above it adjoins the nasal spine of the frontal bone, in front - to the nasal bones, behind - to the sphenoid crest, below - to the vomer, and in front and below - to the cartilaginous part of the nasal septum. Often there is a deviation of all or part of the perpendicular plate to the side.

lattice labyrinth, labyrinthus ethmoidalis, – a paired formation, located on both sides of the perpendicular plate, adjacent to the lower surface of the cribriform plate. Consists of numerous air-carrying lattice cells, cellulae ethmoidales, communicating both with each other and through a series of openings with the nasal cavity. The ethmoid cells are lined with mucous membrane, which is a direct continuation of the nasal mucosa.

The cells located in front open into the middle nasal passage, the middle and posterior ones communicate with the upper nasal passage.

The lateral wall is a thin, smooth orbital plate, lamina orbitalis, forming most of the inner wall of the orbit. The plate connects at the top with the frontal bone, forming the frontoethmoidal suture, sutura fronto-ethmoidalis, below – with the upper jaw – ethmoidomaxillary suture, sutura ethmoidomaxillaris, and with the orbital process of the palatine bone - the palatoethmoidal suture, sutura palato-ethmoidalis, in front - with the lacrimal bone - the lacrimal-ethmoidal suture and behind - with the sphenoid bone - the sphenoethmoidal suture, sutura spheno-ethmoidalis. Along the upper edge of the labyrinth there are two small grooves - the anterior and posterior ethmoidal grooves, which, together with the grooves of the same name in the frontal bone, form tubules that open into the anterior and posterior ethmoidal openings, foramina ethmoidales anterius et posterius, (vessels and nerves of the same name pass through these openings).

The medial wall of the labyrinth is a rough, grooved plate that forms most of the lateral wall of the nasal cavity. On its surface, facing the perpendicular plate, there are two thin processes, slightly curved at the edges and turned outward: the upper one is the superior nasal concha, concha nasalis superior, and the lower one is the middle turbinate, concha nasalis media. Sometimes above the superior nasal concha there is a rudimentary process in the form of a thin bone ridge - the highest nasal concha, concha nasalis suprema. In the superoposterior section of the medial wall of the labyrinth, between the superior and middle nasal conchae, a slit-shaped space is formed - the superior nasal meatus, meatus nasi superior. The gap under the middle turbinate is the middle meatus, meatus nasi medius.

From the inferoanterior surface of each labyrinth, anterior and inferior to the middle turbinate, a hook-shaped process, curved posteriorly and inferiorly, extends processus uncinatus. On the whole skull it connects with the ethmoid process, processus ethmoidalis, inferior nasal concha.

Posterior and superior to the uncinate process is located one of the largest cells, which has the appearance of a swelling - the ethmoidal vesicle, bulla ethmoidalis.

Between the uncinate process below and in front and the large ethmoidal vesicle behind and above there is a gap - the ethmoidal funnel, infundibulum ethmoidae, the upper end of which communicates with the opening of the sinus of the frontal bone. The posterior edge of the uncinate process and the lower surface of the greater ethmoidal vesicle form the cleft semilunaris, hiatus semilunaris, through which the sinus of the maxillary bone communicates with the middle nasal meatus.

Opener

opener, vomer, is an unpaired, diamond-shaped plate that forms the posterior part of the nasal septum.

The vomer, excluding its rear edge, is usually slightly curved to the side,

The upper edge of the opener is thicker than the others. It is separated by a furrow of the vomer, sulcus vomeris, on two processes bent outward - the wings of the vomer, alae vomeris. They are adjacent to the lower surface of the body of the sphenoid bone and cover its beak, forming the sphenoid-vomer suture, sutura sphenomeriana. Such stitches are associated with schindylosis, schyndilesis. This section is the wedge-shaped part of the opener, pars cuneiformis vomeris.

The posterior edge of the bone is the choanal crest, crista choanalis vomeris, slightly pointed, separates the posterior openings of the nasal cavity - choanae, choanae.

The anterior and lower edges are rough. The lower edge connects with the nasal ridge of the upper jaw and palatine bone, and the anterior (oblique) edge connects at the top with the perpendicular plate of the ethmoid bone, and at the bottom with the cartilage of the nasal septum.

Temporal bone

Temporal bone, os temporale, steam room, participates in the formation of the base of the skull and the side wall of its vault. It contains the organ of hearing and balance. It articulates with the lower jaw and is the support of the masticatory apparatus.

On the outer surface of the bone there is an external auditory opening, porus acusticus externus, around which three parts of the temporal bone are located; on top is the scaly part, inwardly and behind is the stony part, or pyramid, in front and below is the tympanic part.
Squamosal part of the temporal bone

scaly part, pars squamosa, has the shape of a plate and is located almost in the sagittal direction. Outer temporal surface facies temporalis, The scaly part is slightly rough and slightly convex. In the posterior section, the groove of the middle temporal artery runs in the vertical direction, sulcus arteriae temporalis mediae

In the posteroinferior part of the scaly part there is an arcuate line, which continues into the lower temporal line, linea temporalis inferior, parietal bone.

From the scaly part, above and slightly anterior to the external auditory opening, the zygomatic process extends horizontally, processus zygomaticus. It is like a continuation of the supramastoid crest, crista supramastoidea, located horizontally along the lower edge of the outer surface of the scaly part. Beginning with a wide root, the zygomatic process then narrows. It has an inner and outer surface and two edges - a longer upper one and a shorter lower one. The anterior end of the zygomatic process is serrated. Zygomatic process of the temporal bone and temporal process, processus temporalis, the zygomatic bones are connected using the temporomygomatic suture, sutura temporozygomatica, forming the zygomatic arch, arcus zygomaticus.

On the lower surface of the root of the zygomatic process there is a transverse oval-shaped mandibular fossa, fossa mandibularis. The anterior half of the fossa, up to the petrosquamosal fissure, is the articular surface, facies articularis, temporomandibular joint. Anteriorly, the mandibular fossa is limited by the articular tubercle, tuberculum articulare.

The outer surface of the scaly part is involved in the formation of the temporal fossa, fossa temporalis, (the bundles of the temporal muscle begin here, m. temporalis).

Inner brain surface facies cerebralis, slightly concave. It has finger-like indentations, impressiones digitatae, as well as the arterial groove, sulcus arteriosus, (it contains the middle meningeal artery, a. meningea media).

The squamous part of the temporal bone has two free edges - the sphenoid and the parietal.

Anteroinferior wedge-shaped edge, margo sphenoidalis, wide, serrated, connects with the scaly edge of the large wing of the sphenoid bone and forms a sphenoid-squamous suture, sutura sphenosquamosa. Superior posterior parietal edge, margo parietalis, pointed, longer than the previous one, connected to the scaly edge of the parietal bone.
Pyramid of temporal bone

Pyramid, rocky part - pars petrosa, the temporal bone consists of posterolateral and anteromedial sections.

The posterolateral portion of the petrous part of the temporal bone is the mastoid process, processus mastoideus, which is located posterior to the external auditory opening. It distinguishes between outer and inner surfaces. The outer surface is convex, rough and is the site of muscle attachment. Inferiorly, the mastoid process passes into a cone-shaped protrusion, which can be easily felt through the skin,

On the inner side, the process is limited by the deep mastoid notch, incisura mastoidea, (the posterior belly of the digastric muscle originates from it, venter posterior m. digastrici). Parallel to the notch and somewhat posteriorly is the groove of the occipital artery, sulcus arteriae occipitalis, (trace of the junction of the artery of the same name).

On the inner, cerebral, surface of the mastoid process there is a wide S-shaped groove of the sigmoid sinus, sulcus sinus sigmoidei, passing at the top into the groove of the same name of the parietal bone and further into the groove of the transverse sinus of the occipital bone (it contains the venous sinus, sinus transversa). Downwards, the groove of the sigmoid sinus continues as the groove of the same name of the occipital bone.

The posterior border of the mastoid process is the jagged occipital margin, margo occipitalis, which, connecting with the mastoid edge of the occipital bone, forms the occipital-mastoid suture, sutura occipitomastoidea. In the middle of the length of the suture or in the occipital edge there is a mastoid foramen, foramen mastoideum, (sometimes there are several of them), which is the location of the mastoid veins, vv. emissariae mastoidea connecting the saphenous veins of the head with the sigmoid venous sinus, as well as the mastoid branch of the occipital artery, ramus mastoideus a. occipitalis.

From above, the mastoid process is limited by the parietal edge, which, at the border with the same edge of the squamous part of the temporal bone, forms the parietal notch, incisura parietalis; the mastoid angle of the parietal bone enters it, forming the parietal-mastoid suture, sutura parietomastoidea.

At the point of transition of the outer surface of the mastoid process into the outer surface of the squamous part, one can notice the remains of the squamous-mastoid suture, sutura squamosomastoidea, which is well expressed on the skull of children.

On the cut of the mastoid process, the bony air cavities located inside it are visible - mastoid cells, cellulae mastoideae. These cells are separated from one another by the bony mastoid walls ( paries mastoideus). The permanent cavity is the mastoid cave, antrum mastoideum, in the central part of the process; mastoid cells open into it, it connects with the tympanic cavity, cavitas tympanica. The mastoid cells and mastoid cave are lined with mucous membrane.

The anteromedial part of the petrous part lies medial to the squamosal part and the mastoid process. It has the shape of a triangular pyramid, the long axis of which is directed from the outside and from behind to the front and medially. The base of the stony part is directed outward and posteriorly; top of the pyramid apex partis petrosae, directed inward and anteriorly.

In the stony part there are three surfaces: anterior, posterior and lower, and three edges: upper, posterior and anterior.

The front surface of the pyramid facies anterior partis petrosae, smooth and wide, facing the cranial cavity, is directed obliquely from top to bottom and forward and passes into the cerebral surface of the scaly part. It is sometimes separated from the latter by a stony-scaly gap, fissura petrosquamosa. Almost in the middle of the front surface there is an arched elevation, eminentia arcuata, which is formed by the anterior semicircular canal of the labyrinth underlying it. Between the elevation and the stony-scaly fissure there is a small platform - the roof of the tympanic cavity, tegmen tympani, under which is the tympanic cavity, cavum tympani. On the anterior surface, near the apex of the petrous part, there is a small trigeminal depression, impressio trigemini, (place of contact of the trigeminal ganglion, ganglion trigeminale).

Lateral to the depression is the cleft of the greater petrosal nerve canal, hiatus canalis n. petrosi majoris, from which the narrow groove of the greater petrosal nerve extends medially, sulcus n. petrosi majoris. Anterior and somewhat lateral to this opening there is a small cleft of the canal of the lesser petrosal nerve, hiatus canalis n. petrosi minoris, from which the groove of the lesser petrosal nerve is directed, sulcus n. petrosi minoris.

Back surface of the pyramid facies posterior partis petrosae, like the anterior one, faces the cranial cavity, but is directed upward and posteriorly, where it passes into the mastoid process. Almost in the middle of it there is a round internal auditory opening, porus acusticus internus which leads to the internal auditory canal, meatus acusticus internus(facial, intermediate, vestibulocochlear nerves pass through it, nn. facialis, intermedius, vestibulocochlearis, as well as the artery and vein of the labyrinth, a. et v. labirinthi). Slightly above and lateral to the internal auditory opening there is a well-defined subarcicular fossa of small depth in newborns, fossa subarcuata, (it includes a process of the dura mater of the brain). Even more lateral lies the slit-like external aperture of the vestibule aqueduct, apertura externa aqueductus vestibuli, opening into the aqueduct of the vestibule, aqueductus vestibuli. The endolymphatic duct emerges from the cavity of the inner ear through the aperture.

The bottom surface of the pyramid facies inferior partis petrosae, rough and uneven, forms part of the lower surface of the base of the skull. On it there is a round or oval jugular fossa, fossa jugularis, (place of contact of the superior bulb of the internal jugular vein).

A small groove is noticeable at the bottom of the fossa (the auricular branch of the vagus nerve passes through it). The groove leads into the opening of the mastoid tubule, canaliculus mastoideus which opens in the tympanomastoid fissure, fissura tympanomastoidea.

The posterior edge of the jugular fossa is limited by the jugular notch, incisura jugularis, which is a small intrajugular process, processus intrajugularis, divides into two parts - anteromedial and posterolateral. Anterior to the jugular fossa lies a rounded opening; it leads to the sleepy canal, nalis caroticus, opening at the top of the rocky part.

Between the anterior circumference of the jugular fossa and the external opening of the carotid canal there is a small stony dimple, fossula petrosa, (place of contact of the inferior ganglion of the glossopharyngeal nerve). In the depths of the dimple there is a hole - a passage into the tympanic canaliculus, canaliculus tympanies, (the tympanic nerve and the inferior tympanic artery pass through it). The tympanic canaliculus leads to the middle ear, auris media, or tympanic cavity, cavum lympani), cavitas tympanis).

Laterally from the jugular fossa, the styloid process, directed downwards and somewhat anteriorly, protrudes, processus styloideus, from which muscles and ligaments begin. In front of the outside of the base of the process, the bony protrusion of the tympanic part descends - the sheath of the styloid process, vagina processus styloidei. Behind the base of the process there is a stylomastoid foramen, foramen stytomastoideum, which is the outlet of the facial canal, canalis facialis.

The top edge of the pyramid marge superior partis petrosae, separates its front surface from the back. A groove of the superior petrosal sinus runs along the edge, sulcus sinus petrosi superioris, - an imprint of the superior petrosal venous sinus lying here and the attachment of the tentorium cerebellum - part of the dura mater of the brain. This groove passes posteriorly into the groove of the sigmoid sinus of the mastoid process of the temporal bone.

Rear edge of the pyramid margo posterior partis petrosae, separates its back surface from the bottom. Along it, on the brain surface, runs the groove of the inferior petrosal sinus, sulcus sinus petrosi inferioris, (trace of contact of the inferior petrosal venous sinus). Almost in the middle of the posterior edge, near the jugular notch, there is a triangular funnel-shaped depression in which the external aperture of the cochlear tubule lies, apertura externa canaliculi cochleae, the cochlear tubule ends in it, canaliculus cochleae.

The anterior edge of the petrous part, located on the lateral side of its anterior surface, is shorter than the upper and posterior ones; it is separated from the scaly part of the temporal bone by a stony-squamosal fissure, fissura petrosquamosa. On it, lateral to the internal opening of the carotid canal, there is an opening of the muscular-tubal canal leading to the tympanic cavity.
Canals and cavities of the petrous part of the temporal bone:

Sleepy channel, canalis caroticus, begins in the middle sections of the lower surface of the stony part with an external opening. Initially, the canal is directed upward, located here in front of the middle ear cavity, then, bending, it follows anteriorly and medially and opens at the apex of the pyramid with an internal opening (the internal carotid artery, accompanying veins and a plexus of sympathetic nerve fibers pass through the carotid canal).
Carotid-tympanic tubules, canaliculi caroticotympanici, are two small tubules that branch from the carotid canal and lead into the tympanic cavity (the carotid-tympanic nerves pass through them).
Facial canal, canalis facialis, begins at the bottom of the internal auditory canal, meatus acusticus internus, (in the field of the facial nerve, area n. facialis). The canal runs horizontally and almost at right angles to the axis of the petrous part, and is directed to its anterior surface, to the cleft of the canal of the greater petrosal nerve, hiatus canalis n. petrosi majoris. Here, turning at a right angle, it forms the elbow of the facial canal, geniculum canalis facialis, and passes to the posterior section of the medial wall of the tympanic cavity (accordingly, on this wall of the tympanic cavity there is a protrusion of the facial canal, prominentia canalis facialis). Next, the canal, heading posteriorly, follows along the axis of the stony part to the pyramidal eminence, eminentia pyramidalis; from here it goes vertically downwards and opens with a stylomastoid foramen, foramen stylomastoideum, (the facial and intermediate nerves, arteries and veins pass through the canal).
Drum string channel, canaliculus chordae tympani, begins on the outer wall of the facial canal, a few millimeters above the stylomastoid foramen. Heading forward and upward, the canaliculus enters the tympanic cavity and opens on its posterior wall (a branch of the intermediate nerve passes through the canaliculus - the chorda tympani, chorda tympani, which, having entered the tympanic cavity through the canaliculus, exits it through the petrotympanic fissure, fissura petrotympanica).
tympanic canaliculus, canaliculus tympanicus, begins on the lower surface of the stony part, in the depths of the stony dimple. Then it goes to the lower wall of the tympanic cavity and, perforating it, enters the tympanic cavity, passes along its medial wall and is located in the promontory groove, sulcus promontorii. Then it follows to the upper wall of the tympanic cavity, where it opens with the cleft of the canal of the lesser petrosal nerve ( hiatus canalis n. petrosi minoris).
Musculo-tubal canal, canalis muculotubarius, is a continuation of the anterosuperior part of the tympanic cavity. The external opening of the canal is located at the notch between the petrous and squamosal parts of the temporal bone, at the anterior end of the petrosquamosal fissure. The canal is located lateral and slightly posterior to the horizontal part of the carotid canal, almost along the longitudinal axis of the petrous part. Horizontally located septum of the muscular-tubal canal, septum canalis musculotubarii, divides the canal into an upper, smaller hemicap of the tensor tympani muscle, semicanals m. tensoris tympani, and the lower larger palucanal of the auditory tube, semicanals lubae auditivae, (in the first lies the muscle that strains the tympanic membrane, the second connects the tympanic cavity with the pharyngeal cavity.
mastoid tubule, canaliculus mastoideus, begins in the depths of the jugular fossa, runs across the lower part of the facial canal and opens in the tympanomastoid fissure (the auricular branch of the vagus nerve passes through the canaliculus).
tympanic cavity, cavum tympani. - an elongated, laterally compressed cavity lined with mucous membrane. Inside the cavity lie three auditory ossicles: the malleus, malleus, anvil, incus, and stirrup ( stages), which, articulating with each other, form a chain of auditory ossicles (more about the structure of these canals, the tympanic cavity, the auditory ossicles and the labyrinth.

Tympanic part of the temporal bone

drum part, pars tympanlca, is the smallest section of the temporal bone. It is a slightly curved ring-shaped plate and forms the anterior, lower walls and part of the posterior wall of the external auditory canal, meatus acusticus extenus. The border tympanic-squamosal fissure is also visible here, fissura tympanosquamosa, which, together with the stony-squamosal fissure, separates the tympanic part from the mandibular fossa of the squamosal part. The outer edge of the tympanic part, closed on top by the scales of the temporal bone, limits the external auditory opening, porus acusticus externus. At the posterosuperior outer edge of this opening there is a supraductal spine, spina suprameatica. Below it is the supraductal fossa, foveola suprameatica. On the border of the larger, internal, and smaller, external, parts of the external auditory canal there is a tympanic groove, sulcus tympanicus, (place of attachment of the eardrum). At the top it is limited by two curved projections: in front - the greater tympanic spine, spina tympanica major, and behind is the small tympanic spine, spina tympanica minor. Between these projections there is a tympanic notch ( incisura tympanica) opening into the supratympanic recess, recessus epitympanicus.

The lower process of the roof of the tympanic cavity is wedged between the medial part of the tympanic part and the squamosal part of the temporal bone. In front of this process there is a stony-scaly fissure, fissura petrosquamosa, and behind - the petrotympanic fissure, fissura petrotympanica, (from the latter the nerve emerges - the chorda tympani and small vessels). Both grooves continue outward into the tympani-squamosal fissure, fissura tympanosquamosa.

The lateral section of the tympanic part passes into the stony ridge, the elongated part of which forms the sheath of the styloid process, vagina processus styloidei. In a newborn, the external auditory canal is still absent and the tympanic part is represented by the tympanic ring, anulus tympanicus, which then grows to form a significant part of the external auditory canal.

On the inner surface of the greater tympanic spine, the spinous crest is clearly visible, at the ends of which there are anterior and posterior tympanic processes, and the malleus groove runs along it.

Parietal bone

Parietal bone, os parietale, steam room, forms the upper and lateral parts of the cranial vault. It has the shape of a quadrangular, convex plate on the outside, in which two surfaces are distinguished: outer and inner - four edges: upper, lower, anterior and posterior.

Outside surface, facies externa, smooth and convex. The place of greatest convexity of the bone is the parietal tubercle, tuber parietale. Below the parietal tubercle, an arched, rough superior temporal line runs horizontally, linea temporalis superior, which starts from the anterior edge of the bone and, being a continuation of the line of the same name of the frontal bone, stretches across the entire surface of the parietal bone to its posterior-inferior corner. Below this line, parallel to the lower edge of the parietal bone, runs another, more pronounced inferior temporal line, linea temporalis inferior, (the first is the site of attachment of the temporal fascia, fascia temporalis, the second - the temporal muscle, m. temporalis).

Inner surface, facies interna, concave; it has faint relief imprints of the adjacent brain in the form of finger-like impressions, impressiones digitatae, and tree-like branching arterial grooves, sulci arteriosi, (traces of the adjacent branches of the middle meningeal artery, a. meningea media).

An incomplete groove of the superior sagittal sinus runs along the upper edge of the inner surface of the bone, sulcus sinus sagittalis superioris. With the groove of the same name on the other parietal bone, it forms a complete groove (a process of the dura mater, the falx cerebri, is attached to the edges of the groove, falx cerebri).

At the back of the same upper edge of the bone there is a small parietal foramen, foramen parietale, through which the branch of the occipital artery passes to the dura mater and the parietal emissary vein. In the depth of the groove of the sagittal sinus and in the vicinity of it (especially on the parietal bones in old age) there are many small pits of granulation, foveolae granulares, (outgrowths come here - granulations of the arachnoid membrane of the brain)).

On the inner surface, at the posteroinferior angle, of the parietal bone lies a deep groove of the sigmoid sinus, sulcus sinus sigmoidei, (imprint of the sigmoid venous sinus of the dura mater). Anteriorly, this groove passes into the groove of the same name of the temporal bone, and posteriorly into the groove of the transverse sinus of the occipital bone.

Superior, sagittal, edge, margosagittalis, straight, strongly jagged, longer than the others, connected with the edge of the same name of the other parietal bone in the sagittal suture, sutura sagittalis. Lower scaly edge, margo squamosus, pointed, arched; its anterior section is covered by the posterior section of the upper edge of the large wing of the sphenoid bone; further posteriorly the scales of the temporal bone are superimposed with their parietal edge; the most posterior portion is connected by teeth to the mastoid process of the temporal bone. According to these three sections, three seams are formed: a scaly seam, sutura squamosa, parietomastoid suture, sutura parietomastoidea, and sphenoid parietal suture, sutura sphenoparietalis.

Anterior, frontal, edge, margo frontalis, toothed; it connects to the parietal edge of the squama of the frontal bone, forming the coronal suture, sutura coronalis.

Posterior, occipital, edge, margo occipitalis, serrated, connects to the lambdoid edge of the occipital bone and forms a lambdoid suture, sutura lamboidea.

Corresponding to the four edges, the parietal bone has four corners:

Anterosuperior frontal angle, angulus frontalis, approaches straight (limited by coronal and sagittal sutures);
anteroinferior wedge-shaped angle, angulus sphenoidalis, acute (limited by the coronal and sphenoparietal sutures);
posterosuperior occipital angle, angulus occipitalis, blunt (limited by the lambdoid and sagittal sutures).
posteroinferior mastoid angle, angulus mastoideus, more obtuse than the posterosuperior one (limited by the lambdoid and parietomastoid sutures); its anterior section fills the parietal notch, incisura parietalis, temporal bone.

Inferior turbinate

inferior nasal concha, concha nasalis inferior, steam room, is a curved bone plate and has three processes: the lacrimal and the ethmoid.

maxillary process, processus maxillaris, forms an acute angle with the bone; the lower edge of the maxillary cleft enters this angle. The process is clearly visible from the side of the maxillary sinus after its opening.

lacrimal process, processus lacrimalis, connects the inferior nasal concha with the lacrimal bone.

ethmoid process, processus ethmoidalis, extends from the junction of the maxillary process with the body of the bone and protrudes into the maxillary sinus. It often fuses with the uncinate process of the ethmoid bone.

The lower shell is strengthened by the anterior section of the upper edge on the conchal ridge of the upper jaw, crista conchalis maxillae, and the posterior section - on the conchal ridge of the perpendicular plate of the palatine bone, crista conchalis lamini perpendicularis os palatini. Under the lower concha there is a longitudinal fissure - the lower nasal meatus, meatus nasi inferior.

Lacrimal bone

lacrimal bone, os lacrimale, steam room, is located in the anterior section of the medial wall of the orbit and has the shape of an oblong quadrangular plate. Its upper edge connects with the orbital part of the frontal bone, forming the frontolacrimal suture, sutura frontolacrimalis, posterior – with the anterior edge of the orbital plate of the ethmoid bone and forms the ethmoidolacrimal suture, sutura ethmoidolacrimalis. The lower edge of the lacrimal bone at the border with the orbital surface of the upper jaw forms the lacrimal-maxillary suture, sutura lacrimomaxillaris, and with the lacrimal process of the inferior concha - the lacrimal-conchaal suture, sutura lacrimoconchalis. In front, the bone connects with the frontal process of the maxilla, forming the lacrimal-maxillary suture, sutura lacrimomaxillaris.

The bone covers the anterior cells of the ethmoid bone and bears on its lateral surface the posterior lacrimal crest, crista lacrimalis posterior, which divides it into the posterior section, the larger one, and the anterior one, the smaller one. The ridge ends with a protrusion - a lacrimal hook, hamulus lacrimalis. The latter is directed to the lacrimal groove on the frontal process of the upper jaw. The posterior section is flattened, the anterior section is concave and forms a tear groove, sulcus lacrimalis. This groove, together with the lacrimal groove of the upper jaw, sulcus lacrimalis maxillae, forms the fossa of the lacrimal sac, fossa sacci lacrimalis which continues into the nasolacrimal duct, canalis nasolacrimalis. The canal opens into the lower nasal passage, meatus nasalis inferior.

Nasal bone

nasal bone, os nasale, steam room, has the shape of a quadrangle, slightly elongated and somewhat convex anteriorly. Its upper edge is connected to the nasal part of the frontal bone, the lateral edge is connected to the anterior edge of the frontal process of the upper jaw.

The anterior surface of the bone is smooth and perforated by one or more holes (a trace of the passage of blood vessels and nerves). The posterior surface is slightly concave and has a ethmoid groove, sulcus ethmoidalis, – trace of the anterior ethmoidal nerve. With their inner, slightly jagged edges, both nasal bones form the internasal suture, sutura intensalis, on which the longitudinal groove is located.

Both bones with their internal surfaces are adjacent to the nasal spine of the frontal bone and the perpendicular plate of the ethmoid bone.

Upper jaw

upper jaw, maxilla, steam room, is located in the upper anterior part of the facial skull. It is one of the air-bearing bones, since it contains a large cavity lined with mucous membrane - the maxillary sinus, sinus maxillaris.

The bone has a body and four processes.

Body of the maxilla corpus maxillae, has four surfaces: orbital, anterior, nasal and infratemporal.

The following bone processes are distinguished: frontal, zygomatic, alveolar and palatine.

orbital surface, facies orbitalis, smooth, triangular in shape, slightly inclined anteriorly, outward and downward, forms the lower wall of the orbit, orbita.

Its medial edge connects in front with the lacrimal bone, forming the lacrimal-maxillary suture, behind the lacrimal bone - with the orbital plate of the ethmoid bone in the ethmoid-maxillary suture, and further posteriorly - with the orbital process of the palatine bone in the palatine-maxillary suture.

The anterior margin of the orbital surface is smooth and forms a free infraorbital margin, margo infraorbitalis, being the lower part of the orbital margin of the orbit, margo orbitalis. On the outside it is serrated and passes into the zygomatic process. Medially, the infraorbital margin forms an upward bend, sharpens and passes into the frontal process, along which the longitudinal anterior lacrimal crest stretches, crista lacrimalis anterior. At the junction with the frontal process, the inner edge of the orbital surface forms the lacrimal notch ( incisura lacrimalis), which, together with the lacrimal hook of the lacrimal bone, limits the upper opening of the nasolacrimal canal.

The posterior edge of the orbital surface, together with the lower edge of the orbital surface of the large wings of the sphenoid bone running parallel to it, forms the inferior orbital fissure, fissura orbitalis inferior. In the middle part of the lower wall of the fissure there is a groove - the infraorbital groove, sulcus infraorbitalis, which, moving anteriorly, becomes deeper and gradually passes into the infraorbital canal, canalis infraorbitalis, (in the groove and to the pala lie the infraorbital nerve, artery and veins). The canal describes an arch and opens on the anterior surface of the body of the upper jaw. In the lower wall of the canal there are many small openings of the dental tubules - the so-called alveolar foramina, foramina alveolaria, nerves pass through them to the group of anterior teeth of the upper jaw.

infratemporal surface, facies infratemporalis, facing the infratemporal fossa, fossa infratemporalis, and pterygopalatine fossa, fossa pterygopalatina, uneven, often convex, forms a tubercle of the upper jaw, tuber maxillae. There are two or three small alveolar openings leading to the alveolar canals, canales alveolares, through which nerves pass to the posterior teeth of the upper jaw.

Front surface fades anterior, slightly curved. Below the infraorbital margin, a rather large infraorbital foramen opens on it, foramen infraorbitale, below which there is a small depression - the canine fossa, fossa canina, (the levator anguli oris muscle originates here, m. levator anguli oris).

Below, the anterior surface, without a noticeable border, passes into the anterior (buccal) surface of the alveolar process, processus alveolaris, on which there is a series of convexities - alveolar elevations, juga alveolaria.

Inwardly and anteriorly, towards the nose, the anterior surface of the body of the upper jaw passes into the sharp edge of the nasal notch, incisura nasalis. Inferiorly, the notch ends in the anterior nasal spine, spina nasalis anterior. The nasal notches of both maxillary bones limit the pyriform aperture ( apertura piriformis) leading into the nasal cavity.

nasal surface, facies nasalis, the upper jaw is more complex. In its upper posterior corner there is an opening - the maxillary cleft, hiatus maxillaris, leading to the maxillary sinus. Posterior to the cleft, the rough nasal surface forms a suture with the perpendicular plate of the palatine bone. Here, a large palatine groove runs vertically along the nasal surface of the upper jaw, sulcus palatinus major. It forms one of the walls of the greater palatine canal, canalis palatinus major. Anterior to the maxillary cleft runs the lacrimal groove, sulcus lacrimalis, limited anteriorly by the posterior edge of the frontal process. Adjacent to the lacrimal groove is the lacrimal bone at the top and the lacrimal process of the inferior concha at the bottom. In this case, the tear trough closes into the nasolacrimal canal, canalis nasolacrimalis. Even more anteriorly on the nasal surface there is a horizontal protrusion - the conchal ridge, crista conchalis, to which the inferior turbinate is attached.

From the upper edge of the nasal surface, at the place of its transition to the anterior one, the frontal process straightens upward, processus frontalis. It has medial (nasal) and lateral (facial) surfaces. The lateral surface of the anterior lacrimal ridge, crista lacrimalis anterior, divides into two sections - front and rear. The posterior portion passes downwards into the lacrimal groove, sulcus lacrimalis. Its border from the inside is the tear edge, margo lacrimalis, to which the lacrimal bone is adjacent, forming with it the lacrimal-maxillary suture, sutura lacrimo-maxillaris. The ethmoidal ridge runs along the medial surface from front to back. crista ethmoidalis. The upper edge of the frontal process is serrated and connects to the nasal part of the frontal bone, forming the frontomaxillary suture, sutura frontomaxillaris. The anterior edge of the frontal process is connected to the nasal bone in the nasomaxillary suture, sutura nasomaxillaris.

Zygomatic process, processus zygomaticus, extends from the outer-superior corner of the body. The rough end of the zygomatic process and the zygomatic bone, os zygomaticum, form the zygomaticomaxillary suture, sutura zygomaticomaxillaris.

palatine process, processus palatinus, is a horizontally located bone plate that extends internally from the lower edge of the nasal surface of the body of the upper jaw and, together with the horizontal plate of the palatine bone, forms a bony septum between the nasal cavity and the oral cavity. The internal rough edges of the palatine processes connect both maxillary bones, forming the median palatine suture, sutura palatina mediana. To the right and left of the suture there is a longitudinal palatine ridge, torus palatinus.

In the median palatal suture, the palatine processes form a sharp marginal projection directed towards the nasal cavity - the so-called nasal ridge, crista nosalis, which is adjacent to the lower edge of the vomer and the cartilaginous septum of the nose. The posterior edge of the palatine process is in contact with the anterior edge of the horizontal part of the palatine bone, forming a transverse palatal suture with it, sutura palatina transversa. The upper surface of the palatine processes is smooth and slightly concave. The lower surface is rough, near its posterior end there are two palatine grooves, sulci palatini, which are separated from one another by small palatine spines, spinae palatinae, (vessels and nerves lie in the grooves). The right and left palatine processes at their anterior edge form an oval incisive fossa, fossa incisiva. At the bottom of the fossa there are incisive holes, foramina incisiva, (there are two of them), with which the incisive canal opens, canalis incisivus, also ending with incisive openings on the nasal surface of the palatine processes. The canal may be located on one of the processes; in this case, the incisive groove is located on the opposite process. The area of ​​the incisive fossa is sometimes separated from the palatine processes by the incisive suture, sutura incisiva), in such cases the incisive bone is formed, os incisivum.

Alveolar ridge ( processus alveolaris), the development of which is associated with the development of teeth, extends downward from the lower edge of the body of the upper jaw and describes an arc directed convexly forward and outward. The lower surface of this area is the alveolar arch, arcus alveolaris. There are holes on it - dental alveoli, alveoli dentales, in which the roots of the teeth are located - 8 on each side. The alveoli are separated from one another by interalveolar septa, septa interalveolaria. Some of the alveoli are in turn divided by interradicular septa, septa interradicularia, into smaller cells according to the number of tooth roots.

The anterior surface of the alveolar process, corresponding to the five anterior alveoli, has longitudinal alveolar elevations, juga alveolaria. The part of the alveolar process with the alveoli of the two anterior incisors represents a separate incisor bone in the embryo, os incisivum, which early merges with the alveolar process of the upper jaw. Both alveolar processes connect and form the intermaxillary suture, sutura intermaxillaris.

Palatine bone

palatine bone, os palatinum- paired bone. It is a curved plate lying in the posterior part of the nasal cavity, forming part of the bottom of this cavity - the bony palate, palatum osseum, and the side wall. It distinguishes between horizontal and perpendicular plates.

horizontal plate, lamina horizon-talis, each of the palatine bones, joining together along the midline of the bony palate, participates in the formation of the posterior part of the median palatal suture, and connecting with the two anterior palatine processes of the maxillary bones, forms a transverse palatine suture, sutura palatina transversa.

Upper, nasal, surface, facies nasa-lis, the horizontal plate faces the nasal cavity, and the lower one is the palatal surface ( facies palatina) is part of the bony palate, palatum osseum, the upper wall of the oral cavity itself, cavitas oris propria.

At the posteromedial end of the horizontal plate there is a posterior nasal spine ( spina nasalis posterior, along the medial edge - the nasal ridge, crista nasalis. The upper surface of each horizontal plate is slightly concave and smooth, the lower surface is rough.

A thick pyramidal process extends backward from the outer part of the base of the perpendicular plate, processus RU- ramidalis. It wedges into the notch between the plates of the pterygoid process of the sphenoid bone and limits the pterygoid fossa below, fossa pterygoidea.

On the lower surface of the pyramidal process there are 1-2 openings - the small palatine foramina, foramina palatina mi-By r a, entrances to the lesser palatine canals, canales palatini minores, in which the nerves of the same name pass. Anterior to them, along the lateral edge of the horizontal plate, on its lower side, the lower edge of the greater palatine groove forms a large palatine foramen with the same edge of the groove on the upper jaw, foramen palatinum majus, which is located in the palatal-maxillary suture.

Perpendicular plate, lamina re r-pendicularis, the palatine bone forms a right angle with the horizontal plate. This thin bony plate is adjacent to the anterior edge of the medial surface of the pterygoid process and to the posterior part of the nasal surface of the body of the maxilla. On the maxillary surface, facies ma-xillaris, there is a large palatine sulcus, sul-cus palatinus major, which, with the groove of the same name in the upper jaw and the pterygoid process, forms the large palatine canal, canalis palatinus major opening on the bony palate with the large palatine foramen, foramen palatinum majus.

On the nasal surface, facies nasalis, perpendicular to the plate of the palatine bone there is a conchal crest, crista concha lis, - a trace of fusion with the posterior part of the nasal concha on it.

Slightly higher is the ethmoid ridge ( crista ethmoidalis), where the middle concha of the ethmoid bone has grown.

The upper edge of the perpendicular wall ends in two processes, the orbital process, processus orbitalis, and wedge-shaped otro c tcom, processus sphenoidalis, which are separated from one another by the sphenopalatine notch, cisura sphenopalatina. The latter, with the body of the sphenoid bone adhering here, forms the sphenopalatine foramen, men sphenopalatinum.

orbital process, processus orbitalis, adjacent to the orbital surface of the jaw; there is often a cell on it that connects to the posterior pits of the ethmoid bone.

sphenoid process, processus sphenoidalis, approaches the lower surface of the sphenoid bone, its shell and the wings of the vomer.

Cheekbone

Cheekbone, os zygomaticum, steam room, enters from the lateral sections of the facial skull. There are three surfaces. The lateral surface faces outwards, facies lateralis, irregularly quadrangular shape is convex, especially in the area of ​​the protruding tubercle.

Inwardly and anteriorly directed concave orbital surface, facies orbitalis, is part of the outer and lower walls of the orbit and meets the lateral surface with a sharp arcuate edge, complementing the infraorbital edge below, margo infraorbitalis.

Temporal surface, facies temporalis, facing the temporal fossa.

The frontal process extends from the upper corner of the body of the bone, processus frontalis. It connects with the zygomatic process of the frontal bone, forming the frontozygomatic suture, sutura frontozygomatica, and with the greater wing of the sphenoid bone, forming the sphenoid-zygomatic suture, sutura sphenozygomatica. Along the posterior edge of the upper third of the frontal process of the zygomatic bone there is a marginal tubercle, tuberculum marginale. On the orbital surface of the frontal process there is often a well-defined orbital eminence, eminentia orbitalis.

Connecting with the upper jaw, the zygomatic bone forms the zygomatic maxillary suture, sutura zygomaticomaxillaris.

On the orbital surface of the bone there is a zygomatic orbital foramen, foramen zygomaticoorbitale, which leads into a canaliculus that bifurcates inside the bone. One branch of this tubule opens on the anterior surface of the bone in the form of the zygomaticofacial foramen, foramen zygomaticofaciale, the other is on the temporal surface in the form of the zygomaticotemporal foramen (nerves pass through these tubules). The orbital eminence is often pronounced on this same surface, eminentia orbitalis.

The temporal process extends from the posterior angle of the zygomatic bone, processus temporalis. It connects to the zygomatic process of the temporal bone through the temporomygomatic suture, sutura temporozygomatica, forming the zygomatic arch, arcus zygomaticus.

Lower jaw

Lower jaw, mandibula, unpaired, forms the lower part of the facial skull. The bone is distinguished by a body and two processes called branches (running upward from the posterior end of the body).

Body, corpus, is formed from two halves connecting along the midline (mental symphysis, symphysis mentalis), which fuse into one bone in the first year of life. Each half is curved with a convex outward. Its height is greater than its thickness. On the body there is a lower edge - the base of the lower jaw, basis man-dibulae, and the upper one - the alveolar part, pars alveolaris.

On the outer surface of the body, in its middle sections, there is a small chin protuberance ( protuberantia mentalis) outward from which the mental tubercle immediately protrudes, tuberculum mentale. Above and outward from this tubercle lies the mental foramen, foramen mentale, (place of exit of blood vessels and nerve). This hole corresponds to the position of the root of the second small molar. An oblique line extends upward from the mental foramen, linea obliqua, which passes into the anterior edge of the ramus of the lower jaw.

The development of the alveolar part depends on the teeth it contains.

This part is thinned and contains alveolar eminences, juga alveolaria. At the top it is limited by an arched free edge - the alveolar arch, arcus alveolaris. There are 16 (8 on each side) dental alveoli in the alveolar arch, alveoli dentales, separated from one another by interalveolar septa, septa interalveolaria.

On the inner surface of the body of the lower jaw, near the midline, there is a single or bifurcated mental spine, spina mentalis, (place of origin of the geniohyoid and genioglossus muscles). At its lower edge there is a depression - the digastric fossa, fossa digastrica, trace of the attachment of the digastric muscle. On the lateral sections of the inner surface, on each side, the mylohyoid line runs obliquely towards the branch of the lower jaw, linea mylohyoidea, (the mylohyoid muscle and the maxillopharyngeal part of the superior pharyngeal constrictor begin here).

Above the maxillary-hyoid line, closer to the hyoid spine, there is a hypoglossal fossa, fovea sublingualis, - a trace of the adjacent sublingual gland, and below and posterior to this line - often a weakly defined submandibular fossa, fovea submandibularis, trace of the attachment of the submandibular gland.

Branch of the lower jaw, ramus mandibulae, is a wide bone plate that rises from the posterior end of the body of the lower jaw upward and obliquely backward, forming an angle of the lower jaw with the lower edge of the body, angulus mandibulae.

On the outer surface of the branch, in the area of ​​the corner, there is a rough surface - a chewing tuberosity ( tuberositas masseterica) trace of attachment of the muscle of the same name. On the inner side, corresponding to the chewing tuberosity, there is a smaller roughness - the pterygoid tuberosity, tuberositas pterygoidea, trace of the insertion of the medial pterygoid muscle.

In the middle of the inner surface of the branch there is a hole in the lower jaw ( foramen mandibulae) limited from the inside and in front by a small bony protrusion - the lingula of the lower jaw ( lingula mandibulae). This hole leads into the mandibular canal, canalis mandibulae, in which blood vessels and nerves pass. The canal lies in the thickness of the spongy bone. On the anterior surface of the body of the lower jaw it has an exit - the mental foramen, foramen mentale.

From the opening of the lower jaw down and forward, along the upper border of the pterygoid tuberosity, the mylohyoid groove runs, sulcus mylohyoideus, (trace of occurrence of vessels and nerves of the same name). Sometimes this groove or part of it is covered with a bone plate, turning into a canal. The mandibular ridge is located slightly above and anterior to the opening of the lower jaw. torus mandibularis.

At the upper end of the ramus of the mandible there are two processes that are separated by the notch of the mandible, incisura mandibulae. Anterior, coronoid, process, processes-sus coronoideus, on the inner surface often has a roughness caused by the attachment of the temporal muscle. Posterior, condylar, process, processus condylaris, ends with the head of the lower jaw, caput mandibulae. The latter has an ellipsoidal articular surface, which participates, together with the temporal bone of the skull, in the formation of the temporomandibular joint, articulatio temporomandibularis.

The head passes into the neck of the lower jaw, collum mandibulae, on the inner half of the circumference of which a pterygoid fossa is noticeable, fovea pterygoidea, - place of attachment of the lateral pterygoid muscle.

Hyoid bone

Hyoid bone, os hyoideum) lies under the body of the tongue, has the shape of a horseshoe and in thin people can be felt through the skin. It is connected to other bones through ligaments. The hyoid bone consists of a body corpus, and large and small horns, cornua majora et cornua minora.

The body of the bone has the shape of a plate, convex anteriorly; it bears transverse and vertical ridges. The upper edge of the plate is pointed, the lower edge is thickened. The lateral edges of the body are connected to the large horns using articular surfaces or fibrous or hyaline cartilage.

Large horns extend from the body of the bone in a posterior and outward direction. They are thinner and longer than the body and have small thickenings at the ends.

The lesser horns extend from the junction of the body of the bone with the greater horns. Sometimes they remain cartilaginous. The small horns are connected to the body of the hyoid bone either through a joint with a weakly stretched capsule, or with the help of connective tissue. Their ends are enclosed in the stylohyoid ligament, lig. stylohyoideum. This ligament sometimes contains one or more small bones.