Extensor reflex. Deviations from the norm


- (pathological foot extensor reflex) is a pathological reflex manifested in the extension of the first toe when its dorsal surface is tingled with a needle. Named after the neurologist Paul Robert Bing, professor of neurology... ... Wikipedia

Oppenheim reflex- (pathological foot extensor reflex) a pathological reflex manifested in the extension of the first toe when running the fingers along the crest of the tibia down to the ankle joint. Named after the German neurologist... ... Wikipedia

Strumpel reflex- (pathological foot extensor reflex) a pathological reflex manifested in the extension of the first toe when the doctor counters (by pressing on the patella) the patient’s conscious attempt to bend the leg at the knee and ... ... Wikipedia

Chaddock reflex- (pathological foot extensor reflex) is a pathological reflex manifested by the extension of the first toe when the skin below the outer ankle is irritated by streaks. Named after the American neurologist Charles Gilbert Chaddock,... ... Wikipedia

Gordon reflex- Gordon's reflex (pathological foot extensor reflex) manifested in the slow extension of the first toe and fan-shaped divergence of other toes when compressed calf muscles. Named after the American neurologist... ... Wikipedia

Schaefer reflex- (pathological foot extensor reflex) a pathological reflex manifested in the extension of the first toe when the Achilles tendon is compressed. Contents 1 Pathophysiology 2 Reflex arc and meaning... Wikipedia

Babinski reflex- File:Babinski sign scheme.jpg Babinski reflex Babinski reflex (pathological foot extensor reflex) is a pathological reflex manifested in the extension of the first toe during line irritation of the skin of the outer edge of the sole.... ... Wikipedia

Reflex- I Reflex (lat. reflexus turned back, reflected) is a reaction of the body that ensures the emergence, change or cessation of the functional activity of organs, tissues or the entire organism, carried out with the participation of the central nervous... ... Medical encyclopedia

Reflex (Jerk)- the body’s response to a particular influence, carried out through the nervous system. For example, the knee jerk reflex (see Patellar reflex) consists of making a sharp tossing movement of the leg that occurs in... ... Medical terms

REFLEX- (jerk) the body’s response to a particular influence, carried out through the nervous system. For example, the knee jerk reflex (see Patellar reflex) consists of making a sharp throwing movement with the leg,... ... Dictionary in medicine

cross extensor reflex- (syn. Philipson reflex) extension of a bent leg while passively flexing the other leg at the hip and knee joints; observed in spastic paraparesis lower limbs as a pathological protective P., as well as normally in children... Large medical dictionary

It was stated above that when isolating spinal segmental reflex mechanisms from the cerebral cortex (damage to the pyramidal tract), in patients, in addition to changes in the normally existing reflexes, a number of pathological reflexes appear that are normally absent. Getting to know them is of great diagnostic importance.

Pathological finger reflexes. All pathological finger reflexes observed in the clinic, depending on the nature of the motor reaction when they are evoked, can be divided into two groups - extensor and flexion.

Extensor reflexes. The most clinically important representative of this group is Babinski’s symptom, which represents the most reliable sign defeats pyramid paths above Lv - S1 segments. It consists in the fact that when a blunt object is passed along the outer edge of the foot from the heel upward, instead of the normal flexion of the fingers, a slow tonic dorsal extension occurs thumb. Sometimes the rest of the toes fan out. Dissociation of the reflex often occurs when only a fan-shaped divergence of the fingers occurs (fan symptom).

What is the essence of this most important pyramidal symptom? Dorsal extension of the thumb is normally associated with other motor components of the complex act of walking. Every time you walk, after the sole touches the ground, dorsal extension of the big toe occurs. Biological significance this movement is obvious; the fact that when the sole is lifted from the ground and when the foot is subsequently brought forward, the big toe does not cling to the ground. This link is closely linked with all other elements of the act of walking and is difficult to isolate from a continuous series of sequential movements. But when the spinal cord is freed from the control of the pyramidal system, the individual components of the complex functional system step reflex begins to appear in isolated form and in all its complete isolation.

Other pathological finger reflexes of the extensor group include the following.

Oppenheim's sign. Tonic extension of the thumb is caused by pressing the flesh of the thumb and index finger along the crest of the tibia from top to bottom.

Gordon's sign. The same effect is obtained by squeezing the patient’s calf muscles with your fingers.

Schaeffer's symptom. Thumb extension is caused by compression of the gastrocnemius tendon.

Grossman's sign. The same effect is sometimes obtained by squeezing the little toe.

Flexion reflexes. The Rossolimo symptom is one of the most important reflexes in this group. It is caused by a short blow of the researcher’s fingers on the flesh of the terminal phalanges of the II-V toes. The response is a reflex plantar flexion of these fingers.

The same reflex on the hands is obtained when applying a short blow to the flesh of the fingers of a pronated hand.

Mendel's - Bekhterev's symptom. The same flexion of the fingers is caused by hitting the front with a hammer. outer surface dorsum of the foot, region IV-V metatarsal bone. The same reflex in the hands is caused by hitting the back of the hand with a hammer.

Zhukovsky's symptom. Plantar flexion of the toes is achieved by applying a short hammer blow to the sole directly under the toes. The same reflex is evoked on the hands when hitting the palmar surface of the hand with a hammer.

Hirshberg's sign. When stroke irritation of the inner edge of the sole results in flexion and rotation of the foot inward.

Wartenberg's sign. With his left hand, the doctor firmly grasps the wrist of the patient’s supinated hand from below. Bent 4 fingers of yours right hand the doctor grabs the patient’s corresponding 4 bent fingers. The patient is asked to continue to bend his fingers as much as possible (against resistance). In this case, the thumb is adducted, bent and turned inward across the palm. In healthy individuals, the thumb remains motionless or its terminal phalanx bends slightly.

Of all the listed pathological reflexes, the extensor reflexes, and of them mainly the Babinski symptom, are the earliest and reliable symptom lesions of the pyramidal tracts. It often occurs when, due to the irradiation of inhibition to the segmental reflex apparatus of the spinal cord, all normal spinal reflexes are suppressed and muscle tone is reduced.

As for the group of flexion reflexes, in most cases they arise in more later periods diseases, often combined with an increase in reflex muscle tone. Some authors attribute the appearance of these reflexes to damage to both the pyramidal and extrapyramidal tracts.

Defense reflex. One of the most striking manifestations of spinal automatism as a consequence of the isolation of spinal reflex mechanisms from the overlying sections is the mentioned protective or defensive reflex. Its essence lies in the fact that when irritation (painful or cold) is applied to the sole of a paralyzed and insensitive leg, reflex flexion of the leg occurs in the hip and knee joints and dorsiflexion of the foot in ankle joint. The reflex is also obtained when stimulation is applied to the entire area located below the lower boundary of the break in the connection between the brain and the spinal cord. The reflex can also be evoked by forced plantar flexion of the thumb or all fingers according to Marie Foix. Sometimes it is possible to obtain a cross protective reflex: in one leg, when irritated, triple flexion (shortening) occurs, in the other - extension (lengthening). Thus, by alternately irritating one or another leg, it is possible to evoke reflex synergy in the form of phase movements of “stepping”. A necessary condition for the appearance of a protective reflex is damage to the pyramidal tracts. However, damage to the pyramids alone is not enough for the emergence of a protective reflex. Obviously, only a more massive lesion across spinal cord with the capture of extrapyramidal pathways in combination with the irritative state of the afferent systems creates the conditions for the emergence of a protective reflex. In the presence of an additional focus of constant irritation (in the dorsal roots and internal organs) patients sometimes have a tendency to constantly flex their legs.

The protective reflex is often used clinically to establish the lower limit of the pathological focus. Top level, up to which the protective reflex is evoked, corresponds to lower limit suspected pathological process.

The protective reflex with upper limbs. It is also caused by painful or cold irritation of the skin. The form of responses depends on the initial position of the affected hand. Most often they are manifested by flexion of the forearm, flexion and pronation of the hand, flexion of the fingers, and less often by extension of the forearm. With pronounced protective reflexes on the hands, the response sometimes takes on the character of rhythmic, sequentially occurring flexion and extension movements of the hand.

One of the variants of the protective reflex can be considered the so-called dorsal adductor reflex. It is examined with a patient sitting with his legs slightly apart. The hammer is used to hit the spinous processes of the vertebrae or, better, paravertebrally (from the sacrum upward or from top to bottom). In patients with lesions of the pyramidal tract, adduction of both hips or one in case of unilateral lesions is observed. The local diagnostic value of the dorsal adductor reflex is the same as the protective one: upper limit, with which the reflex is evoked, corresponds to the lower border of the supposed pathological focus.

Pathological synkinesis. Simultaneously with the appearance of pathological reflexes, damage to the pyramidal tracts is also accompanied by pathological synkinesis - friendly movements. The essence of synkinesis is that, due to the weakening of the inhibitory reactions of the cerebral cortex to the executive-motor apparatus, motor impulses enter not only the corresponding segment, but also radiate to neighboring, sometimes very distant segments of their own and the opposite side. Synkinesias are manifested by a variety of conjugal movements in the affected limbs, both when the muscles on the healthy side are tense, and on the affected limbs when the patient tries to make one or another movement.

There are three main types of synkinesis:

1. Global, or spasmodic, synkinesis: at the moment of strong muscle contraction in healthy limbs with one movement or another, strong muscle tension also occurs on the paralyzed side.

2. Coordination synkinesis: diverse additional synergistic movements that occur during voluntary movements.

3. Imitative synkinesis: in paralyzed limbs, symmetrical movements that the patient makes with healthy limbs are repeated.

An example of global synkinesis can be a test where, when a patient strongly clenches his healthy hand into a fist, the paralyzed arm bends into a elbow joint. Some attribute here the appearance of involuntary movements in paralyzed limbs when coughing, sneezing, yawning, and laughing.

There are a lot of tests to determine coordination synkinesis. This includes the adductor and abductor Raymist’s symptom (if the patient’s healthy leg is abducted or led to resistance when resisting midline, respectively, the paralyzed leg is adducted or abducted), Strumpell's tibial phenomenon (if the patient, with resistance provided by the researcher, tries to bend the paralyzed leg at the knee, simultaneously extension of the foot and sometimes the big toe results), symptom
Grasset-Gossel (when a patient tries to lift a paralyzed leg out of bed, the healthy leg reflexively presses against the bed), etc.

With imitative synkinesis, paralyzed limbs repeat voluntary movements such as flexion and extension of the fingers, pronation and supination of the hand, etc.

These synkinesis are a consequence of damage not only to the pyramidal tracts. Their origins are more complex. Subcortical formations and disruptions of their connections with the cortex play a major role in the occurrence of synkinesis. Most often, pathological synkinesis is observed when the internal capsule is damaged.

Approximately 0.2-0.5 seconds after the stimulus stimulates reflex flexion in one limb, the opposite limb begins to extend. This is called the crossed extensor reflex. Extension of the contralateral limb may push the entire body away from the object causing the painful stimulus in the withdrawn limb.

Nervous mechanism crossed extensor reflex. On right side The figure shows the neural circuit responsible for the crossed extensor reflex, demonstrating that signals from sensory nerves travel to the opposite side of the spinal cord to excite the extensor muscles. Because the cross-extensor reflex typically does not begin until 200 to 500 ms after the onset of the noxious stimulus, many interneurons are recruited into the circuit between the primary sensory neuron and the motor neurons on the contralateral side of the spinal cord responsible for cross-extension.

After removal of the painful stimulus crossed extensor reflex has an even longer aftereffect than the flexion reflex. This long-lasting aftereffect is believed to result from the function of reverberant circuits among the interneurons.

The picture shows a typical myogram, recorded from the muscle involved in the crossed extensor reflex. The myogram demonstrates a relatively long latency period before the onset of the reflex and a long aftereffect after the end of the stimulus. A long aftereffect is useful in keeping the painfully stimulated area of ​​the body at a distance from the pathogenic agent until other nervous reactions lead to the removal of the entire body from the irritant.

Reciprocal inhibition and reciprocal innervation

In previous sections emphasized several times that excitation of one muscle group is often accompanied by inhibition of another muscle group. For example, when the stretch reflex excites one muscle, the antagonist muscle is often simultaneously inhibited. This is a phenomenon of reciprocal inhibition; the neural circuit that provides this reciprocal connection is called reciprocal innervation. Similar reciprocal connections often exist between muscles on two sides of the body, such as the flexor and extensor muscle reflexes outlined earlier.

The picture shows a typical example of reciprocal inhibition. In this case, a moderate but prolonged flexion reflex is excited in one limb of the body; Against the background of this reflex, a stronger flexion reflex is excited in the limb on the other side of the body. This stronger reflex sends reciprocal inhibitory signals to the first limb and reduces the degree of flexion. Finally, removing the stronger reflex allows the primary reflex to regain its previous intensity.


Babinski reflex- slow extension of the big toe (isolated or combined with a fan-shaped divergence of the remaining toes) in response to line irritation of the sole. In children under one year of age it is observed normally. It is caused by deep line irritation applied by the handle of the hammer along the outer edge of the foot from the fifth toe or in the opposite direction (Fig. 9).

Rice. 9. Study of the pathological Babinsky reflex.

Oppenheim reflex- extension of the big toe while holding (with pressure) the flesh of the big toe along the inner edge of the tibia to the foot. The movement should be sliding in the direction from top to bottom (Fig. 10).

Rice. 10. Study of the pathological Oppenheim reflex.

Gordon reflex- extension of the big toe while squeezing the calf muscles with the hand (Fig. 11).

Rice. 11. Study of Gordon's pathological reflex.

Schaeffer reflex- extension of the big toe with compression or pinching irritation of the Achilles tendon (Fig. 12).

Rice. 12. Study of the pathological reflex of Schaefer.

Flexion pathological reflexes

Rossolimo reflex(Fig. 13) - rapid plantar flexion of the II-V toes with abrupt blows to the flesh of these toes with the fingers of the examiner.

Rice. 13. Rossolimo reflex.

Zhukovsky reflex(Fig. 14) - rapid plantar flexion of the II-V toes when struck with a hammer in the middle of the sole, under the toes.

Rice. 14. Zhukovsky reflex.

Bekhterev-Mendelian reflexes- rapid plantar flexion of the II-V toes when tapping with a hammer on the back of the foot, in the area III-IV metatarsal bones(Fig. 15).

Reflex is the body's reaction to external stimuli. If there is a problem with the brain or nervous system Pathological reflexes arise, which are manifested by pathology of motor reactions. In neurological practice, they serve as beacons for identifying various diseases.

The concept of pathological reflex

When the main neuron of the brain or neural pathways are damaged, pathological reflexes occur. They are manifested by new connections between external stimuli and the body’s response to them, which cannot be called the norm. This means that the human body reacts inadequately to physical contact, compared to normal person without pathologies.

Such reflexes indicate some kind of mental or mental state in a person. In children, many reflexes are considered normal (extensor-plantar, grasping, sucking), while in adults the same ones are considered a pathology. At the age of two years, all reflexes are caused by an immature nervous system. Both conditioned and unconditioned reflexes can be pathological. The former manifest themselves as an inadequate response to a stimulus, fixed in memory in the past. The latter are biologically unusual for a given age or situation.

Causes

Pathological reflexes can result from brain lesions and pathologies of the central nervous system, such as:

  • damage to the cerebral cortex by infections, tumor diseases;
  • hypoxia - brain functions are not performed due to lack of oxygen;
  • stroke - damage to the blood vessels of the brain;
  • Cerebral palsy (cerebral palsy) - congenital pathology, in which the reflexes of newborns do not fade over time, but develop;
  • hypertension;
  • paralysis;
  • coma state;
  • consequences of injuries.

Any neural connections or brain diseases can cause incorrect, unhealthy reflexes.

Classification of pathological reflexes

Pathological reflexes are divided into the following groups:

  • Reflexes of the upper limbs. This group includes pathological carpal reflexes, an unhealthy response to external stimuli of the upper extremities. May manifest as involuntary grasping and holding of an object. They occur when the skin of the palms at the base of the fingers is irritated.
  • Reflexes of the lower extremities. These include pathological foot reflexes, reactions to tapping with a hammer in the form of flexion or extension of the phalanges of the toes, and flexion of the foot.
  • Reflexes of the oral muscles are pathological contractions of the facial muscles.

Foot reflexes

Extensor reflexes of the foot are an early manifestation of damage to the nervous system. Pathological is most often tested in neurology. It is a sign of upper motor neuron syndrome. Belongs to the group of reflexes of the lower extremities. It manifests itself as follows: a stroking movement along the outer edge of the foot leads to extension of the big toe. May be accompanied by fanning out all the toes. In the absence of pathology, such irritation of the foot leads to involuntary flexion of the big toe or all the toes. Movements should be light, not causing pain. The reason for the formation of the Babinski reflex is the slow conduction of stimulation along the motor channels and impaired excitation of segments of the spinal cord. In children under one and a half years of age, the manifestation of the Babinski reflex is considered normal, then with the formation of gait and vertical position body he must disappear.

A similar effect can occur with other effects on receptors:

  • Oppenheim reflex - extension of the finger occurs when pressing and moving from top to bottom thumb hands in the area of ​​the tibia;
  • Gordon's reflex - when the calf muscle is compressed;
  • Schaeffer reflex - when the Achilles tendon is compressed.

Pathological flexion reflexes of the foot:

  • Rossolimo reflex - when exposed to jerky blows of a hammer or fingertips on inner surface phalanges, rapid flexion of the II-V toes occurs;
  • ankylosing spondylitis reflex - the same reaction occurs when lightly tapping the outer surface of the foot in the area of ​​​​the metatarsal bones;
  • Zhukovsky reflex - manifests itself when struck in the center of the foot, at the base of the toes.

Oral automaticity reflexes

Oral automatism is the reaction of the oral muscles to a stimulus, manifested by their involuntary movement. Pathological reflexes of this kind are observed in the following manifestations:

  • The nasolabial reflex, which occurs when the base of the nose is tapped with a hammer, is manifested by stretching the lips. The same effect can occur when approaching the mouth (distance-oral reflex) or when lightly striking the lower or upper lip- oral reflex.
  • Palmomental reflex, or Marinescu-Radovic reflex. The stroke movements in the area of ​​the thumb from the side of the palm cause a reaction of the facial muscles and cause the chin to move.

Such reactions are considered normal only for infants; their presence in adults is pathological.

Synkinesis and defensive reflexes

Synkinesis are reflexes characterized by paired movements of the limbs. Pathological reflexes of this kind include:

  • global synkinesia (when the arm is bent, the leg is extended or vice versa);
  • imitation: involuntary repetition of movements of an unhealthy (paralyzed) limb after the movements of a healthy one;
  • coordinator: spontaneous movements of an unhealthy limb.

Synkinesis occurs automatically when active movements. For example, when moving a healthy arm or leg in a paralyzed limb, spontaneous muscle contraction occurs, a flexion movement of the arm occurs, and an extension movement of the legs occurs.

Protective reflexes arise when a paralyzed limb is irritated and are manifested by involuntary movement. An irritant can be, for example, a needle prick. Such reactions are also called spinal automatisms. TO protective reflexes The Marie-Foy-Bekhtereva symptom can be attributed - flexion of the toes leads to involuntary flexion of the leg at the knee and hip joint.

Tonic reflexes

Normally, tonic reflexes appear in children from birth to three months. Their continued manifestation even in the fifth month of life may indicate that the child has cerebral palsy. For children cerebral palsy congenital motor automatisms do not fade away, but continue to develop. These include pathological tonic reflexes:

  • Labyrinthine tonic reflex. It is checked in two positions - on the back and on the stomach - and manifests itself depending on the location of the child’s head in space. In children with cerebral palsy it is expressed in increased tone extensor muscles when lying on the back and flexor muscles when the child lies on his stomach.
  • Symmetrical cervical tonic reflex. In cerebral palsy, it is manifested by the influence of head movements on the tone of the muscles of the limbs.
  • Asymmetrical cervical tonic reflex. It manifests itself as increased muscle tone in the limbs when turning the head to the side. On the side where the face is turned, the extensor muscles are activated, and on the side of the back of the head, the flexor muscles.

With cerebral palsy, a combination of tonic reflexes is possible, which reflects the severity of the disease.

Tendon reflexes

Tendon reflexes are normally caused by hitting the tendon with a hammer. They are divided into several types:

  • Biceps tendon reflex. In response to a hammer blow on it, the arm bends at the elbow joint.
  • Triceps tendon reflex. The arm is bent at the elbow joint, and upon impact, extension occurs.
  • Knee reflex. The blow falls on the underside kneecap. The result is extension of the leg at the knee joint.

Pathological tendon reflexes manifest themselves in the absence of a reaction to hammer blows. They can occur with paralysis, coma, or spinal cord injuries.

Is treatment possible?

Pathological reflexes in neurology are not treated by themselves, since this is not separate disease, but just a symptom of some mental disorder. They indicate problems with the functioning of the brain and nervous system. Therefore, it is necessary, first of all, to look for the reason for their appearance. Only after a doctor has made a diagnosis can we talk about specific treatment, because it is necessary to treat the cause itself, and not its manifestations. Pathological reflexes can only help in determining the disease and its severity.

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