Nuclei of the 7th pair of cranial nerves. Cranial nerves

Contents of the topic "Cranial nerves.":

Branches of the facial nerve (n. facialis) in the facial canal. Greater petrosal nerve, n. petrosus major. Drum string, chorda tympani.
The remaining branches of the facial nerve after exiting the stylomastoid foramen (foramen stylomastoideum). Intermediate nerve, n. intermedius.
Vestibulocochlear nerve (VIII pair, 8 pair of cranial nerves), n. vestibulocochlearis. Parts of the pre-cochlear nerve.
Glossopharyngeal nerve (IX pair, 9 pair of cranial nerves), n. glossopharyngeus. Nuclei of the glossopharyngeal nerve.
Branches of the vagus nerve in the head and neck parts n. vagus
Branches of the vagus nerve in the thoracic and abdominal parts n. vagus Recurrent laryngeal nerve, n. laryngeus recurrens.
Accessory nerve (XI pair, 11 pair of cranial nerves), n. accessorius.
Oculomotor nerve (III pair, 3 pair, third pair of cranial nerves), n. oculomotorius.
Trochlear nerve (IV pair, 4 pair, fourth pair of cranial nerves), n. trochlearis.
Abducens nerve (VI pair, 6 pair, sixth pair of cranial nerves), n. abducens.
Olfactory nerves (I pair, 1st pair, first pair of cranial nerves), nn. olfactorii.
Optic nerve (II pair, 2 pair, second pair of cranial nerves), n. opticus.

N. facialis (n. intermedio-facialis), facial nerve, is mixed nerve; as a nerve of the second branchial arch, it innervates the muscles that developed from it - all facial and part of the sublingual ones and contains efferent (motor) fibers emanating from its motor nucleus to these muscles and afferent (proprioceptive) fibers emanating from the receptors of the latter. It also contains gustatory (afferent) and secretory (efferent) fibers belonging to the so-called to the intermediate nerve, n. intermedius(see below).

According to the components that make it up, n. facialis has three nuclei embedded in the bridge: motor - nucleus motorius nervi facialis, sensitive - nucleus solitarius and secretory - nucleus salivatorius superior. The last two nuclei belong to the nervus intermedius.

N. facialis exits onto the surface of the brain from the side along the posterior edge of the pons, on the linea trigeminofacialis, next to n. vestibulocochlearis. Then it, together with the last nerve, penetrates the porus acusticus interinus and enters the facial canal (canalis facialis). In the canal, the nerve first runs horizontally, heading outward; then in the area of hiatus canalis n. petrosi majoris, it turns back at a right angle and also runs horizontally along the inner wall of the tympanic cavity in its upper part. Having passed the limits of the tympanic cavity, the nerve again makes a bend and descends vertically downwards, leaving the skull through the foramen stylomastoideum.

In the place where the nerve, turning back, forms an angle ( knee, geniculum), the sensitive (taste) part of it forms a small nerve nodule, ganglion geniculi (knuckle node). When leaving the foramen stylomastoideum, the facial nerve enters the thickness of the parotid gland and divides into its terminal branches.

Educational video of the anatomy of the facial nerve and the projection of its branches

VII pair - facial nerve (p. facialis). It is a mixed nerve. It contains motor, parasympathetic and sensory fibers, the last two types of fibers are distinguished as the intermediate nerve.

The motor part of the facial nerve provides innervation to all facial muscles, muscles of the auricle, skull, posterior belly of the digastric muscle, stapedius muscle and subcutaneous muscle of the neck.

In the facial canal, a number of branches arise from the facial nerve.

1. The greater petrosal nerve from the genu ganglion on the outer base of the skull connects with the deep petrosal nerve (a branch of the sympathetic plexus of the internal carotid artery) and forms the nerve of the pterygoid canal, which enters the pterygopalatine canal and reaches the pterygopalatine ganglion. The junction of the greater petrosal and deep petrosal nerves constitutes the so-called Vidian nerve. The nerve contains preganglionic parasympathetic fibers to the pterygopalatine ganglion, as well as sensory fibers from the cells of the genu ganglion. When it is damaged, a peculiar symptom complex occurs, known as neuralgia of the Vidian nerve (Faille's syndrome). The greater petrosal nerve innervates the lacrimal gland. After a break in the pterygopalatine ganglion, the fibers go as part of the maxillary and then zygomatic nerves, anastomose with the lacrimal nerve, which approaches the lacrimal gland. When the greater petrosal nerve is damaged, dry eyes occur due to impaired secretion of the lacrimal gland, and when irritated, lacrimation occurs.

2. The stapedius nerve penetrates the tympanic cavity and innervates the stapedius muscle. By tensing this muscle, conditions are created for best audibility. When innervation is disrupted, paralysis of the stapedius muscle occurs, as a result of which the perception of all sounds becomes sharp, causing painful, unpleasant sensations (hyperacusis).

3. The chorda tympani is separated from the facial nerve in the lower part of the facial canal, enters the tympanic cavity and, through the petrotympanic fissure, exits to the outer base of the skull and merges with the lingual nerve. At the intersection with the inferior alveolar nerve, the chorda tympani gives off a connecting branch to the ear ganglion, in which motor fibers pass from the facial nerve to the levator soft palate muscle.

The chorda tympani carries taste stimuli from the anterior two-thirds of the tongue to the ganglion ganglion and then to the nucleus of the tractus solitarius, to which the taste fibers of the glossopharyngeal nerve approach. As part of the chorda tympani, secretory salivary fibers also pass from the superior salivary nucleus to the submandibular and sublingual salivary glands, previously interrupted in the submandibular and sublingual parasympathetic nodes.

When the facial nerve is damaged, facial asymmetry immediately attracts attention. Typically, facial muscles are examined under motor load. The subject is asked to raise his eyebrows, frown, and close his eyes. Pay attention to the severity of the nasolabial folds and the position of the corners of the mouth. They ask you to show your teeth (or gums), puff out your cheeks, blow out a candle, or whistle. A number of tests are used to identify mild muscle paresis.

Blink test: eyes blink asynchronously due to slower blinking on the paresis side.

Eyelid vibration test: with eyes closed, eyelid vibration is either reduced or absent on the paresis side, which is determined by lightly touching the closed eyelids at the outer corners of the eye with the fingers (especially when pulling the eyelids back).

Orbicularis oris muscle test: on the affected side, the strip of paper is held weaker by the corner of the lips.

Eyelash symptom: on the affected side, with the eyes closed as much as possible, eyelashes are visible better than on the healthy side, due to insufficient closure of the orbicularis oculi muscle.

To differentiate central and peripheral paresis, the study of electrical excitability, as well as electromyography, is important.

The loss of taste sensitivity is called ageusia, its decrease is called hypogeusia, the increase in taste sensitivity is called hypergeusia, and its distortion is called parageusia.

Symptoms of defeat. When the motor part of the facial nerve is damaged, peripheral paralysis of the facial muscles develops - the so-called prosoplegia. Facial asymmetry occurs. The entire affected half of the face is motionless, mask-like, the folds of the forehead and nasolabial fold are smoothed out, the palpebral fissure widens, the eye does not close (lagophthalmos - hare's eye), the corner of the mouth droops. When the forehead wrinkles, folds do not form. When you try to close your eye, the eyeball turns upward (Bell's phenomenon). Increased lacrimation is observed. Paralytic lacrimation is based on constant irritation of the mucous membrane of the eye by air flow and dust. In addition, as a result of paralysis of the orbicularis oculi muscle and insufficient adherence of the lower eyelid to the eyeball, a capillary gap does not form between the lower eyelid and the mucous membrane of the eye, which makes it difficult for tears to move to the lacrimal canal. Due to the displacement of the opening of the lacrimal canal, the absorption of tears through the lacrimal canal is disrupted. This is facilitated by paralysis of the orbicularis oculi muscle and loss of the blink reflex. Constant irritation of the conjunctiva and cornea by the flow of air and dust leads to the development of inflammatory phenomena - conjunctivitis and keratitis.

For medical practice, it is important to determine the location of the lesion of the facial nerve. In the event that the motor nucleus of the facial nerve is affected (for example, in the pontine form of poliomyelitis), only paralysis of the facial muscles occurs. If the nucleus and its radicular fibers are affected, the nearby pyramidal tract is often involved in the process and, in addition to paralysis of the facial muscles, central paralysis (paresis) of the limbs of the opposite side occurs (Millard-Hübler syndrome). With simultaneous damage to the nucleus of the abducens nerve, convergent strabismus on the affected side or gaze paralysis towards the lesion also occurs (Fauville syndrome). If the sensitive pathways at the core level are affected, then hemianesthesia develops on the side opposite to the lesion. If the facial nerve is affected at the point where it exits the brain stem in the cerebellopontine angle, which often happens with inflammatory processes in this area (arachnoiditis of the cerebellopontine angle) or acoustic neuroma, then paralysis of the facial muscles is combined with symptoms of auditory damage (hearing loss or deafness) and trigeminal (absence of corneal reflex) nerves. Since the conduction of impulses along the fibers of the intermediate nerve is disrupted, dry eye occurs (xerophthalmia), and taste is lost in the anterior two-thirds of the tongue on the affected side. In this case, xerostomia should develop, but due to the fact that other salivary glands are functioning, dry mouth is not noted. There is also no hyperacusis, which theoretically exists, but due to combined damage to the auditory nerve is not detected.

Damage to the nerve in the facial canal up to its knee above the origin of the greater petrosal nerve leads, simultaneously with facial paralysis, to dry eyes, taste disturbance and hyperacusis. If the nerve is affected after the origin of the greater petrosal and stapedial nerves, but above the origin of the chorda tympani, then facial paralysis, lacrimation and taste disorders are determined. When the VII pair is damaged in the bone canal below the origin of the chorda tympani or at the exit from the stylomastoid foramen, only facial paralysis with lacrimation occurs. The most common lesion of the facial nerve occurs at the exit from the facial canal and after exiting the skull. Bilateral damage to the facial nerve is possible, even recurrent.

In cases where the corticonuclear tract is affected, paralysis of the facial muscles occurs only in the lower half of the face on the side opposite to the lesion. Hemiplegia (or hemiparesis) often occurs on this side. The peculiarities of paralysis are explained by the fact that part of the nucleus of the facial nerve, which is related to the innervation of the muscles of the upper half of the face, receives bilateral cortical innervation, and the rest - unilateral.

VIII pair - vestibular-cochlear nerve (n. vestibulocochlea-ris). Consists of two roots: lower - cochlear and upper - vestibular. Symptoms of damage. Decreased hearing, increased perception of sounds, ringing, tinnitus, auditory hallucinations. After this, hearing acuity is determined. If there is a decrease (hypacusia) or loss (anacusia) of hearing, it is necessary to determine whether this depends on damage to the sound-conducting (external auditory canal, middle ear) or sound-receiving (organ of Corti, cochlear part of the VIII nerve and its nucleus) apparatus. To distinguish a lesion of the middle ear from a lesion of the cochlear part of the VIII nerve, tuning forks (Rinne and Weber’s technique) or audiometry are used. Since upon entering the pons of the brain, the auditory conductors, in addition to the fact that they are sent to their hemisphere, are also subject to decussation and thus each given The peripheral auditory apparatus turns out to communicate with both hemispheres of the brain, then damage to the auditory conductors above the anterior and posterior auditory nuclei does not cause loss of auditory functions. Unilateral hearing loss or deafness is possible only with damage to the receptor auditory system, the cochlear part of the nerve and its nuclei. In this case, there may be symptoms of irritation (feeling of noise, whistling, buzzing, crackling, etc.). When the cortex of the temporal lobe of the brain is irritated (for example, due to tumors), auditory hallucinations can occur.

The vestibular part (pars vestibularis).

Symptoms of defeat. Damage to the vestibular apparatus - the labyrinth, the vestibular part of the VIII nerve and its nuclei - leads to three characteristic symptoms: dizziness, nystagmus and loss of coordination of movements. Conscious and automatic orientation in space is disrupted: the patient develops false sensations of displacement of his own body and surrounding objects. Dizziness often occurs in attacks, reaches a very strong degree, and can be accompanied by nausea, vomiting.. Rarely, nystagmus is expressed when looking straight; it is usually better identified when looking to the side. Irritation of the vestibular part of the VIII nerve and its nuclei causes nystagmus in the same direction. Switching off the vestibular apparatus leads to nystagmus in the opposite direction.

Damage to the vestibular apparatus is accompanied by abnormal reactive movements, disruption of normal muscle tone and their antagonists. Movements are deprived of proper regulatory influences, hence the incoordination of movements (vestibular ataxia). An unsteady gait appears, the patient deviates towards the affected labyrinth, and in this direction he often falls.

Dizziness, nystagmus and ataxia can be observed with damage not only to the vestibular apparatus, but also to the cerebellum, so it is important to differentiate labyrinthine lesions from similar cerebellar symptoms. Diagnosis is based on the following data: 1) dizziness during labyrinthitis is extremely intense; 2) in the Romberg test, the body tilts to the side with the eyes closed, and there is a dependence on the position of the head and the affected labyrinth; 3) ataxia is always general, i.e., it is not limited to only one limb or limbs of one side, and is not accompanied by intentional tremor, as is observed with cerebellar ataxia; 4) nystagmus with labyrinthine lesions is characterized by a clearly defined fast and slow phase and has a horizontal or rotatory direction, but not vertical; 5) labyrinthine lesions are usually combined with symptoms of damage to the auditory system (for example, tinnitus, hearing loss).

2.37 Symptoms of damage to the 9th and 10th pairs of cranial nerves.

Glossopharyngeus and vagus nerves (n. glossopharyngeus et n. vagus). They have common nuclei that are located in the medulla oblongata in one place, so they are studied simultaneously.

IX pair - glossopharyngeus nerve (n. glossopharyngeus). Contains 4 types of fibers: sensory, motor, gustatory and secretory. Sensitive innervation of the posterior third of the tongue, soft palate, pharynx, pharynx, anterior surface of the epiglottis, auditory tube and tympanic cavity. Motor fibers innervate the stylopharyngeal muscle, which elevates the superior part of the pharynx during swallowing.

Parasympathetic fibers innervate the parotid gland.

Symptoms of defeat. When the glossopharyngeal nerve is damaged, taste disorders are observed in the posterior third of the tongue (hypogeusia or ageusia), loss of sensitivity in the upper half of the pharynx; disturbances in motor function are not clinically expressed due to the insignificant functional role of styloglos-

precise muscle. Irritation of the cortical projection area in the deep structures of the temporal lobe leads to the appearance of false taste sensations (parageusia). Sometimes they can be harbingers (aura) of an epileptic seizure. Irritation of the IX nerve causes pain in the root of the tongue or tonsil, spreading to the velum, throat, and ear.

X pair - vagus nerve (n. vagus). Contains sensory, motor and autonomic fibers. Provides sensory innervation of the dura mater of the posterior cranial fossa, the posterior wall of the external auditory canal and part of the skin of the auricle, the mucous membrane of the pharynx, larynx, upper trachea and internal organs. Motor fibers innervate the striated muscles of the pharynx, soft palate, larynx, epiglottis and upper esophagus .

Autonomic (parasympathetic) fibers go to the heart muscle, smooth muscle tissue of blood vessels and internal organs. The impulses traveling along these fibers slow down the heartbeat, dilate blood vessels, narrow the bronchi, and increase intestinal motility. Postganglionic sympathetic fibers from the cells of the paravertebral sympathetic ganglia also enter the vagus nerve and spread along the branches of the vagus nerve to the heart, blood vessels and internal organs.

Symptoms of defeat. When the periphery of the vagal neuron is damaged, swallowing is impaired due to paralysis of the muscles of the pharynx and esophagus. Liquid food enters the nose as a result of paralysis of the palatine muscles, and the soft palate hangs down on the affected side. With paralysis of the vocal cords, the sonority of the voice is weakened, with bilateral damage - up to aphonia and suffocation. Symptoms of vagal damage include cardiac dysfunction - tachycardia and bradycardia (with irritation). With unilateral damage, symptoms are slightly expressed; with bilateral damage, there are pronounced disorders of swallowing, phonation, breathing and heart function. When the senses of the branches of the vagus are affected, the sense of mucus in the larynx is disrupted, as well as pain in the larynx and ear. When the 9th pair is affected, the taste for bitter and salty things is lost in the back third of the tongue, as well as the feeling of mucus in the upper part of the pharynx.

VII pair - The facial nerve is mixed in function, contains motor, sensory and secretory fibers

Motor fibers innervate all facial muscles, muscles of the ear circumference, occipital, stylohyoid, posterior belly of the digastric muscle, platysma. The motor nucleus of the nerve is located in the pons on the border with the medulla oblongata. The axons of this nucleus bend around the nucleus of the 6th pair under the bottom of the 4th ventricle and form the inner elbow of the 7th pair. At the base of the brain, the facial nerve exits at the cerebellopontine angle and then travels through the internal auditory canal into the fallopian canal. Here the nerve makes another bend (outer knee). The nerve leaves the pyramid of the temporal bone through the stylomastoid foramen, penetrates the parotid salivary gland and splits into terminal branches. In neurological practice, these branches are divided into 2 groups: one innervates the upper facial muscles, the other innervates the lower ones. In the area of the facial nerve canal, a branch departs from the nerve trunk to the stapes muscle, which in its function is an antagonist of m. tensor timpani

The central neurons for the facial muscles are located in the lower part of the precentral gyrus. The axons of these cells go through the corona radiata, the knee of the internal capsule, and the base of the cerebral peduncle. To innervate the upper facial muscles, the fibers approach the peripheral nucleus of both their own and the opposite side. The fibers to that part of the nucleus that innervates the lower part of the facial muscles completely move to the opposite side. Thus, with unilateral damage to the central motor neuron, paralysis occurs not of all, but only of the lower facial muscles of the opposite side. The upper group of facial muscles receives impulses from both hemispheres, so on the side of paralysis you can only notice a slight widening of the palpebral fissure. Central damage to the facial muscles is often combined with the same paresis of the arm (facio-brachial paresis) or the entire half of the body (hemiparesis). When the nucleus or trunk of the nerve is damaged, all facial muscles of the same half of the face are paralyzed

The second portion of the facial nerve, containing sensory and autonomic fibers, passes at the base of the brain between the motor part and the 8th pair. Many authors call this part of the facial nerve the intermediate nerve of Wriesberg (13th pair).

The peripheral sensory neuron is represented by cells of the ganglion geniculi, located in the fallopian canal in the area of the outer genu of the facial nerve. The dendrites of these cells go along with the motor fibers, then move away from it, participating in the formation of the tympanic chord (chorda timpani), some of them end in taste buds in the mucous membrane of the anterior 2/3 of the tongue. The axons of the geniculate ganglion accompany the main trunk of the 7th pair, enter the medulla and end with synaptic connections with the cells of the nucleus tractus solitarii - a continuation of the nucleus of the glossopharyngeal nerve

The intermediate nerve contains effector secretory fibers to the sublingual and submandibular salivary glands. These fibers begin from the nucleus salivatorius superior, located in the pons. Its axons first run in the common trunk of the facial nerve, then pass into the chorda tympani and form synapses with the neurons of the ganglion submandibulare. The fibers of these cells end in the salivary glands. As part of the greater petrosal nerve, parasympathetic secretory fibers pass to the lacrimal gland. Secretory fibers form the efferent parts of the reflex arcs of tear and salivation. Their afferent part is formed by the trigeminal and glossopharyngeal nerves

Study of the facial nerve; examination of the face (there may be asymmetry in the facial muscles at rest, when talking, smiling, laughing). There may be slight muscle twitching or hyperkinesis. Then the patient is asked to wrinkle his forehead, bring his eyebrows together, wrinkle his nose, puff out his cheeks, show his teeth, and whistle. The strength of the orbicularis oculi muscle is also assessed.

Paresis of this muscle causes the inability to completely close the palpebral fissure (lagophthalmos); when trying to close the eyes, the eyeball moves upward (Bell's symptom). Lagophthalmos is usually accompanied by lacrimation, but with high nerve damage there may also be dry eye. When the nerve is damaged above the origin of the stapedius nerve, hyperacusis (increased perception of sounds, especially low ones) and taste disturbance in the anterior 2/3 of the tongue are observed.

For differential diagnosis of peripheral and central lesions, not only the distribution of the affected muscles is taken into account, but also the change in electrical excitability of the nerve and muscles. With peripheral paralysis, a degeneration reaction and a decrease in the corneal and brow reflex are detected.

VIII pair - The vestibulocochlear nerve unites two functionally different sensory parts: the cochlear part. Sound waves are perceived by a special organ of Corti - receptors, to which the dendrites of the spiral ganglion are suitable. The axons of the cells of this node go in the internal auditory canal along with the vestibular nerve. Coming out of the pyramid of the temporal bone, the nerve is located in the cerebellopontine angle and plunges into the brain stem at the posterior edge of the pons. The auditory nerve fibers end in two auditory nuclei: the ventral and dorsal. vestibular ganglion spiral ganglia

From the neurons of the ventral nucleus, the axons are divided into 2 bundles: the larger part passes to the opposite side and ends in the superior olive and trapezoid body, the smaller part approaches the same formations on its side. The axons of the superior olive and the nucleus of the trapezoid body form a lateral loop that ascends and ends in the inferior quadrigeminal body and the internal geniculate body. Some of the fibers of the lateral loop are interrupted in special cells located along the loop itself (the nucleus of the lateral loop itself).

The axons of the dorsal nucleus cells run in the bottom of the rhomboid fossa and, at the level of the midline, plunge into the depths and move both to the opposite side and to their own side (striae acusticae) and then join the lateral lemniscus, contacting the neurons of the posterior geniculate body. Thus, already in the lateral loop there are auditory conductors from both ears.

From the cells of the internal geniculate body, the axons pass as part of the posterior femur of the internal capsule, then, due to the auditory radiation, they end in the transverse gyrus of Heschl of the temporal lobe (fields 41, 42, 20, 21, and 22). Fibers that perceive low sounds end in the oral parts of the gyri, and high ones end in the caudal parts.

Research methodology - study of spoken and whispered speech for each ear - audiometry - test with a tuning fork - Consultation with an otoneurologist

Vestibular part. The vestibular nerve receptors are located inside the ampullae of the three semicircular canals and in two membranous sacs (sacculus and utriculus). Otolith devices are the endings of the dendrites of the cells of the Scarpa vestibular ganglion, located deep in the auditory canal. The axons of these cells form the vestibular nerve, which follows the path of the auditory nerve and penetrates the brain stem.

Near the bottom of the rhomboid fossa, the fibers are divided into ascending and descending branches and end in four nuclei - medial, lateral, superior and inferior. The ascending branch approaches the superior vestibular nucleus of Bechterew, a small part of it is in contact with the nucleus of the cerebellar roof (nucleus fastigii). The descending branches end in the inferior nucleus of Roller, the medial triangular nucleus of Schwalbe and the lateral nucleus of Deiters.

From the lateral nucleus of Deiters, axons form the vestibulospinal fasciculus of Leventhal, which on its own side along the lateral cords approaches the motor cells of the anterior horns. Part of the fibers from this nucleus is directed to the medial longitudinal fascicle of its own and the opposite side and contacts the nuclei of the oculomotor nerves

n. oculomotorus Upper n. trochlearis n. abducens Medial Lateral Inferior tr. vestibulospinalis lateralis fasciculus longitudinalis medialis

From the Schwalbe and Roller nuclei, axons also approach the nuclei of the oculomotor nerve of the opposite side, to the nucleus of the abducens nerve, and from the Bechterew’s nucleus to the nucleus of the 3rd pair of the same side. These vestibuloculomotor fascicles transmit impulses from the vestibular receptors to the external muscles of the eye. These fibers are part of the posterior longitudinal fasciculus and end at the cells of the Darkshevich nucleus and the interstitial nucleus of Cajal. The axons of the neurons of these nuclei transmit impulses to the thalamus, pallidal system and to the cortex (temporal, partially parietal, frontal lobes).

There are numerous connections of the vestibular system with the cerebellum and cells of the reticular formation of the brainstem, as well as with proprioceptive conductors from the spinal cord

Regulation of balance and orientation of the head and body in space is ensured through the medial longitudinal fasciculus, in which there are connections between the vestibular nuclei, the extrinsic muscles of the eye, the cerebellum and the spinal cord. In addition, the vestibular system has been found to play an important role in the perception of gravity.

Examination of the vestibular system In the anamnesis, attention is paid to the presence of dizziness, balance and gait disorders, and tolerance to riding in transport. Another important symptom is vestibular nystagmus: it can be differentiated from cerebellar nystagmus using special caloric, rotational and galvanic tests. Violation of the vestibular reaction leads to vestibular ataxia: a tendency to tilt and fall towards the affected labyrinth. There is no intentional tremors; autonomic reactions: nausea, vomiting, changes in pulse and blood pressure, sometimes fainting. Vestibular symptoms appear when the inner ear, vestibular nerve, or brain stem are damaged.

Traditional diagnostic tests for dizziness Romberg test (used since 1846) The patient stands with his feet together and his eyes closed. A normal person stands upright, but a patient with dizziness deviates from the upright position, making an attempt to compensate for the sense of movement that he perceives. He leans towards the side on which the labyrinth is affected. Barany pointing test (used since 1910) The patient sits on a chair in front of some object. He is asked to close his eyes and point to an object several times. If the labyrinth function is impaired, the patient has the illusion of an object moving and misses the target.

Babinski-Weil test (used since 1913) The patient, with his eyes closed, takes five steps forward and five steps back several times for 30 seconds. If there is a unilateral vestibular lesion, the patient's route will be star shaped. Unterberg test (used since 1938) The patient stands with his eyes closed and stretches his arms forward, holding them horizontally. Then he walks in one place for one minute, raising his knees as high as possible. If there is a vestibular lesion, the patient rotates around its axis.

IX pair - Glossopharyngeal nerve This is a mixed nerve, mainly sensory. Its motor portion is very small, innervates only one stylopharyngeal muscle. The bodies of peripheral neurons form the upper part of the nucleus ambiguus (common with the 10th pair). It is located in the middle part of the medulla oblongata. The axons of these cells emerge between the olive and the rope body, exit the cranial cavity through the jugular foramen and approach the muscle

The central neurons are located in the lower part of the anterior central gyrus, their axons run as part of the corticonuclear pathway and end at both nuclei. Therefore, when one corticonuclear neuron is damaged, swallowing disorders do not occur. Paralysis of one stylopharyngeal muscle occurs rarely and only when the nerve itself is damaged. In this case, the patient experiences difficulty swallowing solid food

The nerve also contains sensory fibers. The first neurons are located in two nodes - ganglion jugularae superius et inferius. The dendrites of these cells branch in the posterior third of the tongue, soft palate, pharynx, pharynx, anterior surface of the epiglottis, auditory tube and tympanic cavity. Fibers from the lower node go to the taste buds of the posterior third of the tongue, and the axons penetrate the medulla oblongata and end in the taste nucleus (nucleus tractus solitarii). The axial-cylindrical processes from the superior node carry conductors of general sensitivity; in the medulla oblongata they approach another nucleus - the nucleus alae cinereaa. The axons of both nuclei move to the opposite side and, as part of the medial loop, go to the thalamus (ventral and medial nucleus).

The fibers of the third neuron pass through the posterior thigh of the internal capsule and end in the cortex around the insula of Reille. Taste sensitivity fibers go to both halves of the thalamus and reach both cortical zones, therefore, if one of the cortical ends of the analyzer is damaged, taste is not affected

Taste testing is carried out using aqueous solutions. It must be borne in mind that normally the sensation of sweet is better perceived by the tip of the tongue, sour - from the lateral surfaces, bitter - from the back third, salty - from the lateral sections and the back third of the tongue. Receptors of the 5th pair take part in the complex perception of taste qualities - the sensation of pungent taste is associated with slight irritation of pain receptors ageusia - loss of taste hypogeusia - decrease parageusia - false taste sensations.

Occasionally, neuralgia of the 9th pair is observed: in the tonsils, the back wall of the pharynx, the back of the tongue and in the depths of the ear. Pain of significant intensity occurs in attacks from several seconds to minutes. The intervals between attacks may vary. Usually one nerve (right or left) is affected. Pair 9 also contains autonomic fibers for the parotid gland

X pair – The vagus nerve has multiple functions. It not only innervates the striated muscles of the digestive and respiratory tracts, but is also the parasympathetic nerve of most internal organs

Motor fibers for the muscles of these areas begin from the nucleus ambiguous cells (common nucleus for 10 and 11 pairs). The axons of these cells form nerve roots that exit from the medulla oblongata between the olive and the rope body, and from the cranial cavity through the jugular foramen along with the glossopharyngeal nerve, innervating the muscles of the soft palate, pharynx, larynx, epiglottis, upper part of the esophagus, vocal cords. The central neurons are located in the lower part of the precentral gyrus, their axons go as part of the corticonuclear pathway to both nuclei located in the medulla oblongata.

As a result, with unilateral damage to the central neuron, dysfunction of this nerve is not observed. When a peripheral neuron (nucleus or nerve itself) is damaged, swallowing (dysphagia) and voice disorders (dysphonia) occur. The 10th pair also contains motor fibers for the smooth muscles of internal organs (bronchi, esophagus, gastrointestinal tract, blood vessels). They begin from the cells of the parasympathetic nucleus nucleus dorsalis nervi vagi.

Peripheral sensory neurons are located in two nuclei - superior and inferior. They are located in the trunk of the vagus nerve at the level of the jugular foramen. The dendrites of ganglion cells end in the occipital portions of the dura mater, the external auditory canal, on the posterior surface of the auricle, in the soft palate, pharynx and larynx. The axons of ganglion cells form 10-15 filaments, which enter between the olive and the rope body and end in the tractus solitarii. The axons of the cells of this nucleus move to the opposite side and, as part of the medial loop, go to the thalamus, where 3 neurons are located. The axons go to the lower part of the postcentral gyrus (cortical area of the larynx and pharynx).

The study consists of assessing the sonority and timbre of the voice (maybe aphonia - silent, whispered speech). Laryngoscopy can detect vocal cord paralysis. Find out how the patient swallows solid and liquid food. When examining the soft palate, its lag during phonation on the affected side and deviation of the tongue to the healthy side are revealed. Both the palatal and pharyngeal reflexes are reduced. With incomplete damage to the 10th pair, disturbances in heart rhythm (tachycardia), respiratory disorders and other internal organs are observed

XI pair – Accessory nerve (accessorius Willisii). This is a purely motor nerve. The bodies of peripheral neurons are located in a column at the base of the anterior horns of cervical segments 1–6. The axons of these cells form 6-7 thin roots, which extend onto the lateral surface of the spinal cord and merge into one common trunk. It rises up, enters the cranial cavity through the foramen magnum and leaves it through the jugular foramen, innervating the sternocleidomastoid and trapezius muscles. The central neurons are located in the middle part of the precentral gyrus between the head and arm zones, they are part of the corticonuclear pathway, at the level of the medulla oblongata they make a partial crossover, and descend to the cells of the nerve nucleus. Unilateral damage to the central neuron leads only to mild paresis of these muscles

The sternocleidomastoid muscle turns the head in the opposite direction and upward. The trapezius muscle raises the shoulder girdle. To study the function of these muscles, force against resistance is assessed. When the nucleus or trunk of the nerve is damaged, atrophy and paresis of the corresponding muscles are observed. The shoulder girdle on the affected side is lowered. Symptoms of irritation are manifested by clonic jerking of the head in the opposite direction, tic-like jerking of the shoulder, and nodding movements. Unilateral tonic spasm causes torticollis.

XII pair - Hypoglossal nerve Peripheral motor neurons are located under the bottom of the rhomboid fossa in the medulla oblongata and in the upper cervical segments. The axons of these cells penetrate between the pyramids and olives in several thin roots and merge into a common trunk, which exits the skull through the canal of the hypoglossal nerve in the lateral part of the occipital bone. These fibers innervate the muscles of the tongue.

The central neurons are located in the lower part of the anterior central gyrus (tongue area), the axons are part of the corticonuclear bundle and at the level of the medulla oblongata pass to the opposite side to the nucleus

The examination begins with examining the tongue in the oral cavity, then asking the tongue to stick out beyond the line of the teeth. With unilateral nerve damage, atrophy of the same half of the tongue is observed. There may be fascicular twitching, which indicates the localization of the process in the nerve nucleus. When protruding, the tongue will deviate to the painful side, because healthy muscles push the tongue more strongly. The orbicularis oris muscle may also suffer to a mild degree, since some of the nerve axons in the periphery pass into the facial nerve.

With bilateral damage, the tongue becomes atrophic and immobile (glossoplegia). Speech becomes disordered and the food bolus in the mouth cannot be pushed through. Unilateral damage to the corticonuclear bundle leads to deviation of the tongue in the opposite direction. There is no atrophy or fasciculations.

Bulbar and pseudobulbar palsies A characteristic feature of the topography of the brain stem is the accumulation of cranial nerve nuclei in a small space. This especially applies to nuclei 5, 9, 10, 12 pairs in the medulla oblongata. These nuclei can be involved in a relatively small pathological focus. In particular, this leads to the development of peripheral paralysis of the tongue, pharynx and larynx.

Clinically, this is manifested by a swallowing disorder - dysphagia, loss of voice sonority - dysphonia, impaired pronunciation of articulate sounds - dysarthria. This symptom complex is called bulbar syndrome. Disorders of swallowing, phonation and articulation can also appear when both hemispheres of the brain are damaged, when the corticonuclear pathways to these cranial nerves are destroyed. This syndrome is called pseudobulbar. Bilateral damage to central neurons is accompanied by the appearance of symptoms of oral automatism: proboscis, nasolabial, distance-oral, palmomental Marinescu - Radovici.

Alternating syndromes In pathological processes in the brain stem, an alternating symptom complex occurs - a syndrome characterized by dysfunction of the cranial nerves on the affected side and motor (and sometimes sensory) disorders on the opposite side

Switching off the nucleus or axons of nerve cells causes peripheral paralysis of the corresponding muscles. Often the lesion involves the adjacent pyramidal, spinothalamic, and bulbothalamic tracts. In their purest form, alternating syndromes are observed in vascular diseases of the brain. Alternating syndromes are usually divided according to the level of damage to the brain stem

Syndromes of damage to the medulla oblongata Wallenberg-Zakharchenko syndrome - occurs when the posterior inferior cerebellar artery is blocked. Characterized by damage to pairs 9, 10, descending nucleus of pair 5, descending sympathetic tract, inferior cerebellar peduncle, spinothalamic tract, RF, vestibular nerves and vomiting center. Clinically manifested by paralysis of half the muscles of the pharynx, soft palate and vocal cords, Horner's syndrome, cerebellar disorders, sensory disturbances on the face of the bulbous type on the affected side, dissociated sensitivity disorders on the opposite side. Patients experience dizziness, nausea, and vomiting. Nystagmus. Avellis syndrome - paralysis of the soft palate and vocal cord on the side of the lesion and hemiparesis on the opposite side

Syndromes of damage to the pons Milyar-Gubler syndrome - peripheral paresis of facial muscles on the side of the lesion and hemiplegia on the opposite side. Foville syndrome - paresis of the facial muscles, abducens nerve on the side of the lesion and paresis of the limbs on the opposite side. Raymond-Sestan syndrome - ataxia and choreoathetoid movements on the side of the lesion, hemiparesis and sensitivity disorders on the opposite side

Syndromes of midbrain lesions Weber's syndrome - ptosis, mydriasis, divergent strabismus, impaired movements of the eyeball up, down, inward on the side of the lesion, and on the opposite side - hemiparesis of the central type. Benedict's syndrome - on the side of the lesion there is paralysis of the oculomotor nerve, on the opposite side there is mild spastic hemiparesis in combination with choreoathetosis and intention tremor in the paralyzed limbs. Parinaud's syndrome - superior gaze paresis, convergence disorder, partial bilateral ptosis on the side of the lesion; on the opposite side there may be pyramidal symptoms.

TWELVE PAIRS OF CRANIAL NERVES

Compiled by Academician of the Russian Academy of Medical Sciences, Doctor of Medical Sciences, Professor of the Department of Normal Anatomy of Moscow State Medical University, Pavlova Margarita Mikhailovna

Twelve pairs of cranial nerves:

I pair of cranial nerves – n. olfactorius – olfactory nerve;

II pair of cranial nerves – n. opticus – optic nerve;

III pair of cranial nerves – n. oculomotorius – oculomotor nerve;

IV pair of cranial nerves – n. trochlearis – trochlear nerve;

V pair of cranial nerves – n. trigeminus – trigeminal nerve;

VI pair of cranial nerves – n. abducens – abducens nerve;

VII pair of cranial nerves – n. facialis – facial nerve;

VIII pair of cranial nerves – n. vestibulocochlearis – static auditory nerve;

IX pair of cranial nerves – n. glossopharyngeus – glossopharyngeal nerve;

X pair of cranial nerves – n. vagus – vagus nerve;

XI pair of cranial nerves – n. accessorius – accessory nerve;

XII pair of cranial nerves – n. hypoglossus – hypoglossal nerve.

I pair of cranial nerves n . olfactorius – olfactory nerve , sensitive. It develops from the olfactory brain - an outgrowth of the forebrain, so there are no nodes. From the nasal cavity (from receptors) - the posterior sections of the superior and middle turbinates → 18-20 filaments (filae olfactoriae) - these are the central processes of the olfactory cells → regio olfactoria (olfactory area) → lamina cribrosa ossis ethmoidalis → bulbus olfactorius (olfactory bulb) → tractus olfactorius (tract) → trigonum olfactorium (olfactory triangle).

In pathology: decreased, increased, absent or perverted (olfactory hallucinations) sense of smell.

II pair of cranial nerves n . opticus – optic nerve , by function – sensitive. It is an outgrowth of the diencephalon and is connected to the midbrain. Has no nodes. Starts from the rods and cones on the retina → canalis opticus → chiasma optici (optic chiasm), at the level of the sella thurcica in the sulcus chiasmatis of the sphenoid bone. Only the medial bundles intersect → tractus opticus → corpus geniculatum laterale → pulvinar thalami → superior colliculi. It ends in the occipital lobe - sulcus calcarinus.

When damaged, the visual fields of one’s own or someone else’s eye are lost:

If the optic nerve is damaged: blindness, decreased vision, visual hallucinations.

III pair of cranial nerves n . oculomotorius – oculomotor nerve . The function is mixed, but predominantly motor for the eye muscles. It has motor and parasympathetic nuclei - (nucleus accessorius). It leaves the brain along the medial edge of the cerebral peduncle → fissura orbitalis superior → into the orbit

ramus superior (to m. rectus superior, to m. levator palpebrae superior)

ramus inferior (to m. rectus inferior et medialis and to m. obliquus inferior)

Root → to ganglion celiare with parasympathetic fibers – for m. sphincter pupillae and m. ciliaris.

Triad of symptoms when n. is affected. oculomotorius:

1) Ptos (drooping of the upper eyelid) – lesion of m. levator palpebrae superior.

2) Divergent strabismus (innervation of the VI pair of cranial nerves predominates) → stropismus divergens.

3) Pupil dilation (damage to m. sphincter pupillae). The dilator (mydrias) predominates.

The superior, inferior, and medial rectus muscles are innervated by the third pair of cranial nerves.

The external rectus muscle of the eye is the VI pair of cranial nerves.

The superior oblique muscle of the eye is the fourth pair of cranial nerves.

The inferior oblique muscle of the eye is the third pair of cranial nerves.

The muscle that lifts the upper eyelid (m. levator palpebrae superior – III pair of cranial nerves (antagonist of the VII pair of cranial nerves for m. orbicularis oculi).

M. sphincter pupillae (pupil constrictor) – III pair of cranial nerves (parasympathetic branch as part of the n. oculomotorius).

M. dilatator pupillae (muscle that dilates the pupil) is an antagonist of the constrictor. Innervated by the sympathetic nervous system.

IV pair of cranial nerves n . trochlearis - trochlear nerve. By function - motor. It leaves the superior cerebral velum, goes around the cerebral peduncle → fissura orbitalis superior, enters the orbit. Innervates the superior oblique muscle of the eye – m. obliquus oculi superior. In pathology, double vision due to the slanted position of the eyeballs, as well as a symptom of the impossibility of descending from the stairs.

V pair of cranial nerves n . trigeminus – trigeminal nerve. Functionally, it is a mixed nerve. Contains motor, sensory and parasympathetic fibers. Innervates all masticatory muscles, facial skin, teeth, and glands of the oral cavity.

1) one motor and three sensory nuclei;

2) sensory and motor roots;

3) trigeminal ganglion on the sensitive root (ganglion trigemenale);

5) three main branches: ophthalmic nerve, maxillary nerve, mandibular nerve.

The cells of the trigeminal ganglion (ganglion trigemenale) have one process, dividing into two branches: central and peripheral.

Central neurites form a sensory root - radix sensoria, enter the brain stem → sensory nerve nuclei: pontine nucleus (nucleus pontis nervi trigemini), nucleus of the spinal tract (nucleus spinalis nervi trigemini) - hindbrain, nucleus of the midbrain tract - nucleus mesencephalicus nervi trigemini - middle brain.

The peripheral processes are part of the main branches of the trigeminal nerve.

Motor nerve fibers originate in the motor nucleus of the nerve - nucleus motorius nervi trigemini (hindbrain). Coming out of the brain, they form a motor root - radix motoria.

The autonomic nerve ganglia are associated with the main branches of the trigeminal nerve.

1) Ciliary ganglion – with the optic nerve;

2) Pterygopalatine ganglion – with the maxillary nerve;

3) Auricular and submandibular - with the mandibular nerve.

Each branch of the trigeminal nerve (ophthalmic, maxillary, mandibular) gives off:

1) branch to the dura mater;

2) branches to the mucous membrane of the oral cavity, nose, to the paranasal (paranasal, accessory) sinuses;

3) to the organs of the lacrimal gland, salivary glands, teeth, eyeball.

I. N. ophthalmicus– optic nerve

By function - sensitive. Innervates the skin of the forehead, lacrimal gland, part of the temporal and parietal region, upper eyelid, dorsum of the nose (upper third of the face). Passes through fissura orbitalis superior.

Branches: lacrimal nerve (n. lacrimalis), frontal nerve (n. frontalis), nasociliary nerve (n. nasociliaris).

N. lacrimalis innervates the lacrimal gland, the skin of the upper eyelid, and the outer canthus.

n. supraorbitalis (supraorbital nerve) through incisura supraorbitalis - to the skin of the forehead;

n. supratrochlearis (supratrochlear nerve) - for the skin of the upper eyelid and medial canthus.

N. nasociliaris. Its final branch is n. infratrochlearis (for the lacrimal sac, medial corner of the eye, conjunctiva).

nn. ciliares longi (long ciliary branches) – to the eyeball,

n. ethmoidalis posterior (posterior ethmoid nerve) – to the paranasal sinuses (sphenoid, ethmoid).

n. ethmoidalis anterior – to the frontal sinus, nasal cavity: rr. nasales medialis et lateralis, r. nasalis externus.

The autonomic ganglion of the first branch of the V pair of cranial nerves is the ciliary ganglion ciliare. It lies on the outer surface of the optic nerve (in the orbit) between the posterior and middle thirds. Formed from three sources:

a) sensitive root – radix nasociliaris (from n. nasociliaris);

b) parasympathetic – from n. oculomotorius;

c) sympathetic – radix sympathicus from plexus sympaticus a. ophthalmica.

II. N. maxillaris– maxillary nerve– for the middle third of the face, mucous membrane of the nasal cavity and mouth, upper lip. Enters through foramen rotundum.

r. meningeus (to dura mater) in the pterygopalatine fossa;

nodal branches – rr. ganglionares – sensitive branches to ganglion pterygopalatinum;

zygomatic nerve (n. zygomaticus);

infraorbital nerve (n. infraorbitalis).

The autonomic ganglion of the second branch of the V pair of cranial nerves is the pterygopalatine ganglion - ganglion pterygopalatinum. Formed from three sources:

a) sensitive root – nn. pterygopalatini;

b) parasympathetic root – n. petrosus major (VII pair of cranial nerves + n. intermedius);

c) sympathetic root – n. petrosus profundus (from plexus caroticus internus).

From ganglion pterygopalatinum depart: rr. orbitales (orbital branches), rr. nasales posteriores superiores (posterior superior nasal branches), nn. palatine (palatine branches).

Rr. orbitalis through fissura orbitalis inferior → into the orbit, then from n. ethmoidalis posterior → to the ethmoidal labyrinth and sinus sphenoidalis.

Rr. nasales posteriores → through foramen sphenopalatinum → into the nasal cavity and are divided into: rr. nasales posteriores superiores lateralis and rr. nasales posteriores superiores medialis.

Nn. palatini → through canalis palatinus and are divided into: n. palatinus major (via foramen palatinum major), nn. palatini minores (via foramina palatina minora), rr. nasales posteriores inferiores (for the posterior parts of the nasal cavity).

N. zygomaticus (zygomatic nerve) → through the foramen zygomaticoorbitale exits and divides into: r. zygomaticofacialis and r. zigomaticotemporalis (exit through the holes of the same name). It enters the orbit from the pterygopalatine fossa through fissura orbitalis inferior.

N. infraorbitalis (infraorbital nerve). From the pterygopalatine fossa → fissura orbitalis inferior → sulcus infraorbitalis → foramen infraorbitale.

nn. alveolares superiores posteriores innervate the posterior third of the teeth of the upper jaw. Pass through foramina alveolaria posteriora to tuber maxillae → canalis alveolaris, form a plexus;

nn. alveolares superiores medii (1-2 stems). They extend within the orbit or pterygopalatine fossa. Innervates the middle third of the teeth of the upper jaw;

nn. alveolares superiores anteriores (1-3 stems) – for the anterior upper teeth of the upper jaw.

From n. infraorbitalis depart:

nn. alveolares superiores (for teeth);

rr. palpebrales inferiores (for the eyelids);

rr. nasales externi;

rr. nasales interni;

rr. labiales superiores – for the upper lip.

III. N. mandibularis –mandibular nerve. The nerve is mixed. Its branches:

a) r. meningeus – with a. meninfea media passes through the foramen spinosum. The nerve is sensitive to the dura mater.

b) n. massetericus – for the muscle of the same name;

c) nn. temporales profundi – for the temporal muscle;

d) n. pterygoideus lateralis – for the muscle of the same name;

e) n. pterygoideus medialis – for the muscle of the same name;

n. pterygoideus medialis: n. tensor tympani, n. tensor veli palatini – for the muscles of the same name.

e) n. buccalis, sensitive (buccal nerve) – for the buccal mucosa.

g) n. auriculotemporalis – auriculotemporal nerve, sensitive, passes anterior to the external auditory canal, pierces the glandula parotis, goes to the temple area: rr. auricularis, rr. parotidei, n. meatus acusticus externus, nn. auriculares anteriores.

h) n. lingualis (lingual), sensitive. It is joined by the chorda tympani (drum string) → continued n. intermedius. Contains secretory fibers to the submandibular and sublingual nerve ganglia + taste fibers to the papillae of the tongue.

Branches n. lingualis: rr. isthmi faucium, n. sublingualis, rr. linguales.

Ganglion submandibulare (submandibular ganglion) is formed from three sources:

a) nn. linguales (sensitive, from n. trigeminus);

b) chorda tympani – parasympathetic nerve from the VII pair of cranial nerves (n. intermedius);

c) plexus sympaticus a facialis (sympathetic).

Vegetative node of the third branch n. trigeminus innervates the submandibular and sublingual salivary glands.

Ganglion oticum (ear node) – vegetative node n. mandibularis. It lies under the foramen ovale, on the medial surface of n. mandibularis. It is formed by three sources:

a) n. mandibularis – sensitive branches (n. auriculotemporalis, n. meningeus);

b) n. petrosus minor – parasympathetic nerve – terminal branch of n. tympanicus (IX pair of cranial nerves);

c) plexus sympathicus a. meningea media.

Ganglion oticum innervates the salivary gland through n. auriculotemporalis.

i) n. alveolaris inferior (lower alveolar nerve) – mixed. Mostly sensitive to the teeth of the lower jaw, forming a plexus. Leaves the channel via foramen mentale. Enters the canal through the foramen mandibulare of the lower jaw.

n. mylohyoideus (for venter anterior m. digastrici and m. mylohyoideus);

rr. dentales et gingivales – for the gums and teeth of the lower jaw;

n. mentalis – mental nerve – continuation of the trunk n. alveolaris inferior. From the canalis mandibularis exits through the foramen mentale.

Its branches:

rr. mentales (for the skin of the chin);

rr. labiales inferiores (for the skin and mucous membrane of the lower lip).

VI pair of cranial nerves n . abducens - abducens nerve. By function - motor. Innervates the external rectus muscle of the eye - m. rectus oculi lateralis. If the internal rectus muscle of the eye (III pair of cranial nerves) prevails, there will be a convergent strabismus (stropismus convergens). The core is located in the bridge. Enters the orbit through the fissura orbitalis superior along with the III, IV pairs of cranial nerves + the first branch of the V pair of cranial nerves.

VII pair of cranial nerves n . facialis – facial nerve. The nerve is mixed, mainly motor for facial muscles.

Has three cores in the bridge:

From the linea trigeminofacialis with the VIII pair (n. vestibulocochlearis) passes into the porus acusticus internus → canalis facialis.

There are three directions of the nerve in the canal:

Horizontally (in the frontal plane), then sagittal, then vertical. It leaves the skull through the foramen stylomastoideum. Between the first and second parts a bend in the form of a knee is formed - genu n. facialis with the formation of ganglion geniculi (geniculate node) as a result of the attachment of n. intermedius, therefore below the knee there are branches with a vegetative function.

In pathology: an open eye on the affected side and a skew of the face to the healthy side, impaired salivation, lack of taste for sweets, smoothed nasolabial fold, drooping corner of the mouth, dry eyeball.

Branches in the pyramid of the temporal bone:

1) n. stapedius – to m.stapedius (“stapes” – stirrup). Motor nerve.

2) n. petrosus major, secretory nerve, autonomic. Derived from genu n.facialis. It leaves the pyramid through hiatus canalis n. petrosi majoris → sulcus n. petrosi majores → canalis pterygoideus together with the sympathetic nerve – n. petrosus profundus from plexus caroticus internus. Both nerves form n. canalis pterygoidei → ganglion pterygopalatinum: rr. nasales posteriores, nn. palatini.

Part of the fibers through n. zygomaticus (from n.maxillaris) through connections with n. lacrimalis reaches the lacrimal gland.

Branches n. facialis, forming in the glandula parotis plexus parotideus and a large crow's foot - pes anserina major.

3) Chorda tympani – from the vertical part of the nerve. The chorda tympani is an autonomic, parasympathetic nerve.

N. intermedius (intermediate nerve), mixed. Contains:

1) taste fibers - to the sensitive nucleus - nucleus tractus solitarii

2) efferent (secretory, parasympathetic) fibers from the autonomic nucleus – nucleus solivatorius superior.

N. intermedius emerges from the brain between n. facialis and n. vestibulocochlearis, joins the VII pair of cranial nerves (portio intermedia n. facialis). Then it passes into chorda tympani and n. petrosus major.

Sensitive fibers arise from ganglion geniculi cells. The central fibers of these cells → to the nucleus tractus solitarii.

Chorda tympani regulates the taste sensitivity of the anterior parts of the tongue and soft palate.

Secretory parasympathetic fibers from n. intermedius begin from the nucleus solivatorius superior → along the chorda tympani → sublingual and submandibular salivary glands (through the ganglion submandibulare and along the n. petrosus major through the ganglion pterygopalatinum - to the lacrimal gland, to the glands of the mucous membrane of the nasal cavity and palate).

The lacrimal gland receives secretory fibers from n. intermedius through n. petrosus major, ganglion pterygopalatinum + anastomosis of the second branch of the V pair of cranial nerves (n. maxillaris with n. lacrimalis).

N. intermedius innervates all facial glands except glandula parotis, which receives secretory fibers from n. glossopharyngeus (IX pair of cranial nerves).

VIII pair of cranial nerves n . vestibulocochlearis – vestibulocochlear nerve ( n . statoacousticus ). The nerve is sensitive. The fibers come from the organ of hearing and balance. Consists of two parts: pars vestibularis (balance) and pars cochlearis (hearing).

The pars vestibularis - ganglion vestibulare node lies at the bottom of the internal auditory canal. The pars cochlearis - ganglion spirale node lies in the cochlea.

The peripheral processes of the cells end in the perceptive devices of the labyrinth. The central processes - porus acusticus internus - into the nuclei: pars vestibularis (4 nuclei) and pars cochlearis (2 nuclei).

In pathology, hearing and balance are impaired.

IX pair of cranial nerves n . glossopharyngeus - glossopharyngeal nerve. Functionally – mixed. Contains: a) afferent (sensitive) fibers from the pharynx, tympanic cavity, posterior third of the tongue, tonsils, palatine arches;

b) efferent (motor) fibers innervating m. stylopharyngeus;

c) efferent (secretory) parasympathetic fibers for glandula parotis.

Has three cores:

1) nucleus tractus solitarii, receiving the central processes of the ganglion superior et inferior;

2) vegetative nucleus (parasympathetic) – nucleus solivatorius inferior (lower salivary). Has cells scattered in formatio reticularis;

3) motor nucleus, common with n. vagus – nucleus ambiguus.

It leaves the skull with the X pair of cranial nerves through the foramen jugulare. Within the opening, a node is formed - ganglion superior, and under it - ganglion inferior (the lower surface of the pyramid of the temporal bone).

1) N. tympanicus (from ganglion inferior → cavum tympani → plexus tympanicus with plexus sympaticus a. crotis interna (for the auditory tube and tympanic cavity) → n. petrosus minor (exits through the hole on the upper wall of the tympanic cavity) → sulcus n. petrosi minores → ganglion oticum (parasympathetic fibers for the parotid salivary gland as part of the n. auriculotemporalis (from the third branch of the V pair of cranial nerves).

2) R. m. stylopharyngei – to the pharynx muscle of the same name;

3) Rr. tonsillares – to the arches, palatine tonsils;

4) Rr. pharyngei – to the pharyngeal plexus.

X pair of cranial nerves n . vagus – vagus nerve. Mixed, predominantly parasympathetic.

1) Sensitive fibers come from the receptors of internal organs and blood vessels, from the dura mater, meatus acusticus externus to the sensitive nucleus – nucleus tractus solitarii.

2) Motor (efferent) fibers - for the striated muscles of the pharynx, soft palate, larynx - from the motor nucleus - nucleus ambiguus.

3) Efferent (parasympathetic) fibers - from the vegetative nucleus - nucleus dorsalis n. vagi – to the heart muscle (bradycardia), to the smooth muscles of blood vessels (dilate).

Composed of n. vagus goes n. depressor – regulates blood pressure.

Parasympathetic fibers narrow the bronchi, trachea, innervate the esophagus, stomach, intestines to the colon sigmoideum (increase peristalsis), liver, pancreas, kidneys (secretory fibers).

It comes out of the medulla oblongata. In foramen jugulare forms ganglion inferior.

Peripheral cell processes are part of the sensitive branches from the receptors of the viscera and blood vessels - meatus acusticus externus. The central processes end in the nucleus tractus solitarii.

A. Head part:

r. memningeus – to the dura mater;

r. auricularis – to the external auditory canal.

B. Neck part:

rr. pharyngei → plexus in the pharynx with the IX pair of cranial nerves + truncus sympathicus;

n. laryngeus superior: sensory branches for the root of the tongue, motor branches for m. cricothyreoideus anterior (the remaining muscles of the larynx are innervated by n. laryngeus inferior from n. laryngeus recurrens);

rr. cardiaci superiores (for the heart).

B. Thoracic part:

n. laryngeus recurrens;

r. cardiacus inferior (from n. laryngeus recurrens);

rr. bronchiales et trachleares - to the trachea, bronchi;

rr. esophagei - to the esophagus.

G. Abdominal part:

truncus vagalis anterior (together with fibers of the sympathetic nervous system);

truncus vagalis posterior;

plexus gastricus anterior;

plexus gastricus posterior → rr. celiaci.

XI pair of cranial nerves n . accessorius - accessory nerve. Motor for m. sternocleidomastoideus and m. trapezius. It has two motor nuclei in medulla oblongata and medulla spinalis → nucleus ambiguus + nucleus spinalis.

It has two parts: head (central), spinal.

XI pair – split off part n. vagus The head part connects to the spinal portion and exits the skull through the foramen jugulare along with the IX and X pairs of cranial nerves.

The spinal portion is formed between the roots of the spinal nerves (C 2 -C 5) of the upper cervical nerves. Enters the cranial cavity through the foramen occipitale magnum.

If the XI pair of cranial nerves is damaged, torticollis is a tilt of the head to the healthy side with a turn in the direction of the lesion.

XII pair of cranial nerves n . hypoglossus - hypoglossal nerve. Motor, mainly for the muscles of the tongue and neck muscles. It carries sympathetic fibers from the superior cervical sympathetic ganglion. There is a connection with n. lingualis and with the lower node n. vagus The somatic motor nucleus is in the trigonum nervi hypoglossi of the rhomboid fossa → formation reticularis, descending through the medulla oblongata. At the base of the brain - between the olive and the pyramid → canalis n. hypoglossi. Forms the upper wall of the Pirogov triangle – arcus n. hypoglossi.

The branch of the XII pair connects with the cervical plexus, forming ansa cervicalis (innervates the muscles below the os hyoideum) - m. sternohyoideus, m. sternothyreoideus, m. thyreohyoideus and m. onohyoideus.

When n. is affected. hypoglossus, the protruding tongue deviates towards the lesion.

VII pair, n. facialis - motor nerve. Core n. facialis is located quite deep in the lower part of the pons, at its border with the medulla oblongata (om. Fig. 23, 24 and 50). Fibers emanating from the cells of the nucleus rise dorsally to the bottom of the rhomboid fossa and bend around the nucleus n located here from above. abducentis (VI nerve), forming the so-called knee (internal) of the facial nerve.

Next, the fibers are directed downwards and emerge as a root at the base between the pons and the medulla oblongata (see Fig. 22), lateral to the olive, in the pontocerebellar angle (together with the n. intermedius Wrisbergi and n. acusticus), following in the direction of the porus acusticus internus. At the base of the meatus acusticus, the facial and Wrisberg nerves depart from the auditory nerve and enter the canalis facialis Fallopii (see Fig. 27). Here, in the pyramid of the temporal bone, the VII nerve again forms a knee (external) and finally exits the skull through the foramen stylomastoideum, dividing into a number of terminal branches (“crow's foot”, pes anserinus). N. facialis is the motor nerve of the facial muscles and innervates all facial muscles (except for the m. levator palpebrae superioris - III nerve), m. digas-tricus (posterior abdomen), m. stylo-hyoideus and, finally, m. stapedius and m. platysma myoides on the neck. For a considerable distance, the travel companion of the facial nerve is n. intermedius Wrisbergi, also called the XIII cranial nerve.

This is a mixed nerve, having centripetal sensory, more precisely, taste, and centrifugal secretory salivary fibers. In terms of its significance, it is in many ways identical to the glossopharyngeal nerve, with which it has common nuclei. Sensitive taste fibers begin from the cells of the ganglion geniculi, located in the genu canalis facialis, in the temporal. bones. They go to the periphery along with n. facialis no to the fallopian canal and leave the latter as part of the chorda tympani (Fig. 28); later they enter the trigeminal nerve system and through r. lingualis n.. trigemini reach the tongue, supplying its anterior two thirds with taste endings (the posterior third is innervated from the glossopharyngeal nerve). Axons of cells n. intermedii from ganglion geniculi together with n. facialis enter the brain stem at the cerebellopontine angle and end in the “taste” nucleus, the nucleus tractus solitarius, which is common with the IX nerve.

The secretory salivary fibers of the XIII nerve arise from the nucleus salivatorius, common with the IX nerve, and pass together with the n. facialis, leaving canalis facialis as part of the same chordae tympani; they innervate submandibular and sublingual salivary glands(glandula submaxillaris and glandula sublingualis). Except n. Wrisbergi, along a certain length accompany the facial nerve and secretory lacrimal fibers, starting from a special secretory nucleus located near the nucleus of the VII nerve. Together with n. facialis, these fibers enter the falliopian canal, which soon leaves as part of the p. petrosus superficial - is major. In the future lacrimal fibers enter the trigeminal nerve system and through n. lacrimalis(V nerve) reach the lacrimal glands. When these fibers are damaged, there is no lacrimation and the eye becomes dry.

Slightly below the origin of n. petrosus superficialis major are separated from. facial nerve and leave the fallopian canal and fibers n. stapedii. When the muscle of the same name innervated by it is damaged, hyperakusis is observed (unpleasant, increased perception of sound, especially low tones).

Below these two branches emerges from the bony canal and separates from the facial nerve chorda tympani- continuation n. Wrisbergi with its taste fibers for the anterior two-thirds of the tongue and salivary fibers for the submandibular and sublingual glands (see Fig. 28).

Damage to the VII nerve causes peripheral paralysis of the facial muscles (prosopoplegia). Even with a simple examination, the sharp asymmetry of the face is striking (Fig. 29). The affected side is mask-like, the folds of the forehead and the nasolabial fold are smoothed here, the main fissure is wider, the corner of the mouth is lowered. When the forehead wrinkles, no folds form on the side of paralysis (the m. frontalis is affected); When you close your eyes, the palpebral fissure does not close (lagophtalmus) due to weakness of m. orbicularis oculi. In this case, the eyeball moves upward (Bell's phenomenon), moreover on the affected side than on the healthy side 17 . With lagophthalmos, increased lacrimation is usually observed (for exceptions, see below). When showing teeth, the corner of the mouth on the affected side is not pulled back (m. risorius), and the m. platysma myoides on the neck. Whistling is impossible, speech is somewhat difficult (m. orbicularis oris). As with any peripheral paralysis, a degeneration reaction is observed, the brow reflex is lost or weakened(and corneal). The height of the lesion of the facial nerve should be determined depending on the symptoms accompanying the described picture.

When the nucleus or fibers inside the brain stem are damaged (see Fig. 28), damage to the facial nerve is accompanied by central paralysis or paresis of the limbs of the opposite side (alternating Millard-Gubler syndrome), sometimes with the addition of lesion n. abducentis (Fauville syndrome).

Damage to root n. facialis at the site of its exit from the brain stem is usually combined with lesions of n. acustici (deafness) and other symptoms of damage to the cerebellopontine angle (see Fig. 22). Facial nerve paralysis in these cases is not accompanied by lacrimation (dry eye), there is a disturbance of taste in the anterior two-thirds of the tongue, and dry mouth may be felt. Hyperakusis is not observed due to concomitant damage to the VIII nerve.

During processes in the area of the bone canal up to genu n. facialis, i.e. above the origin of n. petrosi superficial- is majoris, Along with paralysis, dry eyes, taste disturbances and salivation are also noted(see Fig. 28); on the hearing side there is hyperakusis(damage to fibers of n. stapedii).

With a lesion in the bone canal below the origin of n. petrosi, the same disorders of taste, salivation and hyperakusis are observed along with paralysis, but instead of dry eye, increased lacrimation occurs.

In case of damage to the facial nerve in the bone canal below origins n. stapedii and above chordae tympan i (see Fig. 28) are observed paralysis, lacrimation, taste and salivation disorders.

Finally, if the nerve is damaged in the bone below the origin of the chordae tympani or already after it leaves the skull through the foramen stylo-mastoideum observed only paralysis with lacrimation without those accompanying symptoms discussed with higher lesions.

The most common are the latter cases with peripheral localization of the process, and the paralysis is usually unilateral. Cases of diplegiae facialis are quite rare. It should be noted that with peripheral paralysis of the facial nerve, especially at the onset of the disease, pain in the face, in the ear and in its circumference (especially often in the mastoid region) is very often observed. This is explained by the presence on the face of rather intimate connections (anastomoses) with branches of the trigeminal nerve, the possible passage of sensory fibers of the V nerve into the canalis facialis (chorda tympani - canalis Fallopii - n. petrosis superficialis major), simultaneous involvement of the facial nerve and the trigeminal root in the process nerve or its node during processes at the base of the brain (see Fig. 22).

Central paralysis(paresis) of the facial muscles are observed, as a rule, in combination with hemiplegia. Isolated lesions of the facial muscles of the central type are rare and are sometimes observed with damage to the frontal lobe or only the lower part of the anterior central gyrus. It is clear that central paresis of the facial muscles is the result of a supranuclear lesion of the tractus cortico-bulbaris in any part of it (cerebral cortex, corona radiata, capsula interna, cerebral peduncles, pons). With central paralysis, the upper facial muscles (m. frontalis, m. orbicularis oculi) are almost not affected, and only the lower (oral) muscles are affected. This is explained by the fact that the upper cell group of the nucleus of the VII nerve has bilateral cortical innervation, in contrast to the lower one, the cells of which are approached by fibers of the central nerves (tractus cortico-bulbaris) mainly only from the opposite hemisphere. With central paralysis of the facial muscles, unlike peripheral paralysis, a degeneration reaction will not be observed; the brow reflex is preserved and even strengthened.

To the phenomena irritation in areas of the facial muscles include various kinds of tics (a manifestation of neurosis or organic disease), contractures that may be a consequence of peripheral paralysis of the VII nerve, localized spasm, other clonic and tonic convulsions (cortical or subcortical hyperkinesis).

Anatomy. The facial nerve originates in the pontine nucleus, located on the border with the medulla oblongata, posterior and lateral to the abducens nerve nucleus. Its central part innervates the facial muscles of the lower part of the same half of the face and is connected only with the opposite hemisphere of the brain. The dorsal part innervates the muscles of the upper parts of the face with both hemispheres of the brain.

The fibers emerging from the nucleus loop around the nucleus of the abducens nerve, forming the internal knee of the FN. Then they go outward and ventrally to the cerebellopontine angle, in the region of which they exit the substance of the brain. Next, the facial nerve enters through the internal auditory opening of the petrous part (pyramid) of the temporal bone into the internal auditory canal, and from it penetrates into the canal of the facial nerve. In the initial part of this canal, it is joined by the intermediate nerve, which contains sensory (taste) and autonomic (secretory) fibers. Sensitive fibers are connected to the nucleus, and secretory fibers are connected to the superior salivary nucleus, common nuclei with the glossopharyngeal nerve. In the bone canal, the facial nerve makes a bend (outer knee of the FN). At this point, the facial nerve thickens due to the genu ganglion, which belongs to the sensitive part of the intermediate nerve. Having left the canal, the FN passes through the parotid gland and is divided into two branches - upper and lower, from which many nerve branches are formed, innervating mainly the facial muscles of the same half of the face.

The following branches arise in the area of the facial nerve canal: the greater petrosal nerve, the stapedial nerve and the chorda tympani. The greater petrosal nerve innervates the lacrimal gland, the stapedius nerve - the muscle of the same name, and the chorda tympani provides taste innervation of the anterior 2/3 tongue and innervates the sublingual and submandibular salivary glands.

The branches extending from the facial nerve after leaving the stylomastoid foramen innervate: the posterior auricular nerve - the muscles of the auricle, the posterior belly of the digastric muscle and the stylohyoid muscle; temporal branches - frontalis muscle, orbicularis oculi muscle, frowning muscle; zygomatic branches - the orbicularis oculi muscle and the zygomatic muscle, buccal branches - the zygomatic major, buccal, laughter muscle, orbicularis oris and nasal muscles; marginal branch of the lower jaw - mental muscle, lips; cervical branch - muscles of the neck.

Symptoms of defeat.

a) paralysis of facial muscles

1. central: smoothness of the nasolabial fold and drooping of the corner of the mouth on the side opposite to the lesion (since the upper part of the FN nucleus is connected to both hemispheres, and the lower part - only to the opposite, therefore, with supranuclear lesions of the FN, only the lower parts of the facial muscles are affected)

2. peripheral: paralysis of all facial muscles of the same half of the face: it is impossible to wrinkle the forehead; when closing the eye, the eyeball turns upward, and its iris goes under the upper eyelid and only the sclera is visible (Bell's symptom); the eye does not close (hare's eye - lagophthalmos); when teeth are bared, the corner of the mouth is pulled to the healthy side, and the smoothness of the nasolabial fold on the affected side becomes even more pronounced; whistling is impossible, speech is difficult; while eating, food gets behind the affected cheek; lacrimation; the brow reflex is lost or weakened; When studying electrical excitability, a degeneration reaction is possible.

The long-term existence of peripheral paralysis may be accompanied by the development of contracture of the affected muscles, which leads to a narrowing of the palpebral fissure and strengthening of the nasolabial fold on the affected side. Sometimes pathological synkinesis of the facial muscles occurs. In this case, squinting the eye is accompanied by baring the teeth, and an attempt to bare the teeth causes squinting of the eye on the affected side.

b) in pathological processes accompanied by irritation of the nuclear cells or fibers of the facial nerve, a tonic muscle spasm is observed - facial hemispasm (the mouth and tip of the nose are pulled to the affected side, the eye is closed, the chin muscles are contracted, the subcutaneous muscle of the neck is tense).

Diagnosis of the level of damage:

a) at the base of the skull: taste disorders in the anterior 2/3 of the tongue, paralysis of facial muscles, dry eyes, decreased salivation and decreased hearing or deafness in the same ear. The latter is caused by damage to the auditory nerve running next to the facial nerve.

b) in the initial part of the facial canal: paralysis of facial muscles, taste disorder in the anterior 2/3 of the tongue, dry eyes, decreased salivation and increased perception of various tastes (hyperacusis), which is associated with impaired innervation of the stapedius muscle.

c) in the canal area, downward from the greater petrosal nerve, above the chorda tympani: paralysis of the facial muscles on the same half of the face, lacrimation, taste disturbance on the anterior 2/3 of the tongue and decreased salivation

d) after exiting the stylomastoid foramen: paralysis of facial muscles and lacrimation, taste remains.

When both LNs are affected, the face is amicable, as if clad in a mask, its usual folds are absent, closing the eyelids is difficult, so the eyeballs remain half-open, it is impossible to fold the lips into a tube and close the mouth. In case of increased mechanical excitability of the facial nerve, Chvostek's symptom appears (tapping with a hammer on the zygomatic arch causes muscle contraction on the same half of the face).

Sometimes, with lesions of the facial nerve, pain is possible, which is explained by the presence of its nerve connections with the trigeminal nerve.

Research methods: the state of innervation of the facial muscles is mainly determined; taste sensitivity on the anterior 2/3 of the tongue for sweet and sour is also examined.