Which cranial nerve is mixed in function. Cranial Nerve Injuries

Olfactory nerve(n. olfactorius).

Receptor olfactory cells are scattered in the epithelium of the mucous membrane of the olfactory region of the nasal cavity. The thin central processes of these cells are assembled into olfactory threads, which are actually the olfactory nerve. From the nasal cavity, the nerve enters the cranial cavity through the holes of the ethmoid bone and ends in the olfactory bulb. From the cells of the olfactory bulb, the central olfactory pathways begin to the cortical zone of the olfactory analyzer in the temporal lobe of the brain.

Bilateral complete loss of smell (anosmia) or its decrease (hyposmia) is often the result of a disease of the nose or is congenital (sometimes in this case it is combined with some endocrine disorders). Unilateral olfactory disorders are mainly associated with a pathological process in the anterior cranial fossa (tumor, hematoma, traumatic brain injury, etc.). Unusual paroxysmal olfactory sensations (parosmia), more often than some indefinite unpleasant odor, are harbingers of an epileptic seizure caused by irritation of the temporal lobe of the brain. Irritation of the temporal lobe of the brain can cause a variety of olfactory hallucinations.

Research methodology. The study of smell is carried out using a special set of aromatic substances (camphor, mint, valerian, pine extract, eucalyptus oil). The subject, with his eyes closed and one half of his nose pinched, is brought odorous substances and asked to say what smell he smells, whether he perceives the smells of each nostril equally well. Do not use substances with strong odors (ammonia, acetic acid), because. in this case, irritation of the endings of the trigeminal nerve occurs, so the results of the study will be inaccurate.

Damage symptoms. They differ depending on the level of damage to the olfactory nerve. The main ones are the loss of smell - anosmia, the decrease in smell - hyposmia, the increase in smell - hyperosmia, the perversion of smell - dysosmia, olfactory hallucinations. For the clinic, one-sided decrease or loss of smell is mainly important, because. bilateral hypo- or anosmia is caused by the phenomena of acute or chronic rhinitis.

Hypoosmia or anosmia occurs when the olfactory pathways are affected up to the olfactory triangle, i.e. at the level of the first and second neurons. Due to the fact that the third neurons have a cortical representation both on their own and on the opposite side, a cortical lesion in the olfactory projection field does not cause a loss of smell. However, in cases of irritation of the cortex of this area, sensations of non-existent odors may occur.

The proximity of the olfactory filaments, the olfactory bulb and the olfactory tract to the base of the skull leads to the fact that during pathological processes on the base of the skull and brain, the sense of smell is also disturbed.

optic nerve(n. opticus).

It is formed by axons of neurons of the ganglionic layer of the retina, which exit the eyeball through the cribriform plate of the sclera as a single trunk of the optic nerve into the cranial cavity. On the basis of the brain in the region of the Turkish saddle, the fibers of the optic nerves converge on both sides, forming the optic chiasm and optic tracts. The latter continue to the external geniculate body and the pillow of the thalamus, then the central visual path goes to the cerebral cortex (occipital lobe). Incomplete intersection of the fibers of the optic nerves causes the presence in the right optic tract of fibers from the right halves, and in the left optic tract - from the left halves of the retinas of both eyes.

Damage symptoms.

With a complete break in the conduction of the optic nerve, blindness occurs on the side of damage with the loss of a direct pupillary reaction to light. With the defeat of only part of the fibers of the optic nerve, focal loss of the visual field (scotoma) occurs. With the complete destruction of the chiasm, bilateral blindness develops. However, in many intracranial processes, the defeat of the chiasm can be partial - a loss of the outer or inner halves of the visual fields develops (heteronymous hemianopia). With a unilateral lesion of the visual tracts and overlying visual pathways, a unilateral loss of visual fields occurs on the opposite side (homonymous hemianopsia).

Damage to the optic nerve can be inflammatory, congestive and dystrophic; detected by ophthalmoscopy. The causes of optic neuritis can be meningitis, encephalitis, arachnoiditis, multiple sclerosis, influenza, inflammation of the paranasal sinuses, etc. They are manifested by a decrease in visual acuity and narrowing of the field of view, which is not corrected by the use of glasses. Congestive optic papilla is a symptom of increased intracranial pressure or impaired venous outflow from the orbit. With the progression of congestion, visual acuity decreases, blindness may occur. Optic nerve atrophy can be primary (with dorsal tabes, multiple sclerosis, optic nerve injury) or secondary (as an outcome of neuritis or congestive nipple); there is a sharp decrease in visual acuity up to complete blindness, narrowing of the field of view.

Ocular fundus- part of the inner surface of the eyeball visible during ophthalmoscopic examination (optic disc, retina and choroid). The optic disc stands out against the red background of the fundus as a rounded formation with clear boundaries and a pale pink color. In the posterior pole of the eye is the most sensitive area of ​​the retina - the so-called yellow spot, which has the shape of a horizontally located oval of a yellowish tint. The macula is made up of cones, which provide daytime vision and are involved in the accurate perception of the shape, color, and details of an object. As you move away from the macula, the number of cones decreases, and the number of rods increases. The rods have a very high light sensitivity and provide the perception of objects at dusk or at night.

Research methodology. Find out if there are complaints of decreased visual acuity, loss of visual field, the appearance of sparks, dark spots, flies, etc.

Visual acuity is examined using special tables on which letters are depicted in rows. Moreover, each lower row is smaller than the previous one. On the side of each row is a number indicating from what distance the letters of this row should be read with normal visual acuity.

The visual fields are examined using the perimeter. Often it is necessary to use an approximate method of measuring fields of view. To do this, a person sits with his back to the light source, closes one eye, but without pressing on the eyeball. The examiner sits down in front of the patient, asks to fix the patient's gaze at some point in front of him, leads the hammer from the patient's ear around the circumference to the bridge of the nose, while asking the patient to report when he sees him. The external field of view is usually 90 degrees. The inner, upper and lower visual fields are examined in a similar way and are 60, 60, 70 gr. respectively.

Color perception is studied using special polychromatic tables, on which numbers, figures, etc. are depicted in spots of different colors.

The fundus is examined using an ophthalmoscope and a photo-ophthalmoscope, which allows you to get both black and white and color pictures of the fundus.

Oculomotor nerve. (n. oculomotorius).

Innervates the external muscles of the eye (with the exception of the external rectus and superior oblique), the muscle that lifts the upper eyelid, the muscle that narrows the pupil, the ciliary muscle, which regulates the configuration of the lens, which allows the eye to adapt to near and far vision.

System III pair consists of two neurons. The central one is represented by the cells of the cortex of the precentral gyrus, the axons of which, as part of the cortical-nuclear pathway, approach the nuclei of the oculomotor nerve of both their own and the opposite side.

A wide variety of functions performed by the III pair is carried out with the help of 5 nuclei for the innervation of the right and left eyes. They are located in the brain peduncles at the level of the superior colliculus of the roof of the midbrain and are peripheral neurons of the oculomotor nerve. From two large cell nuclei, the fibers go to the external muscles of the eye on their own and partially opposite side. The fibers that innervate the muscle that lifts the upper eyelid come from the nucleus of the same and opposite sides. From two small cell accessory nuclei, parasympathetic fibers are sent to the muscle, the constrictor pupil, of their own and the opposite side. This ensures a friendly reaction of the pupils to light, as well as a reaction to convergence: constriction of the pupil with simultaneous contraction of the direct internal muscles of both eyes. From the posterior central unpaired nucleus, which is also parasympathetic, the fibers are sent to the ciliary muscle, which regulates the degree of bulge of the lens. When looking at objects located near the eye, the bulge of the lens increases and at the same time the pupil narrows, which ensures clarity of the image on the retina. If accommodation is disturbed, a person loses the ability to see the clear contours of objects at different distances from the eye.

The fibers of the peripheral motor neuron of the oculomotor nerve start from the cells of the above nuclei and exit the legs of the brain on their medial surface, then pierce the dura mater and then follow in the outer wall of the cavernous sinus. The oculomotor nerve leaves the skull through the superior orbital fissure and enters the orbit.

Damage symptoms.

Violation of the innervation of individual external muscles of the eye is due to damage to one or another part of the large cell nucleus, paralysis of all the muscles of the eye is associated with damage to the nerve trunk itself. An important clinical sign that helps to distinguish between damage to the nucleus and the nerve itself is the state of innervation of the muscle that lifts the upper eyelid and the internal rectus muscle of the eye. The cells from which the fibers go to the levator muscle, the upper eyelid, are located deeper than the rest of the cells of the nucleus, and the fibers going to this muscle in the nerve itself are located most superficially. The fibers that innervate the internal rectus muscle of the eye run in the trunk of the opposite nerve. Therefore, when the trunk of the oculomotor nerve is damaged, the fibers that innervate the muscle that lifts the upper eyelid are the first to be affected. Weakness of this muscle or complete paralysis develops, and the patient may either only partially open the eye or not open it at all. With a nuclear lesion, the muscle that lifts the upper eyelid is one of the last to be affected. With the defeat of the core, "the drama ends with the curtain falling." In the case of a nuclear lesion, all the external muscles on the side of the lesion are affected, with the exception of the internal straight line, which is switched off in isolation on the opposite side. As a result of this, the eyeball on the opposite side will be turned outward due to the external rectus muscle of the eye - divergent strabismus. If only the large cell nucleus suffers, the external muscles of the eye are affected - external ophthalmoplegia. Because if the nucleus is damaged, the process is localized in the brain stem, then the pyramidal tract and fibers of the spinothalamic tract are often involved in the pathological process, Weber's alternating syndrome occurs, i.e. defeat of the third pair on one side and hemiplegia on the opposite side.

The nerves that leave and enter the brain are called cranial nerves. The distribution and a brief description of them separately is considered in the next article.

Types of nerves and pathology

There are several types of nerves:

• motor;
• mixed;
• sensitive.

The neurology of the motor cranial nerves, both sensitive and mixed, has pronounced manifestations that specialists can easily diagnose. In addition to an isolated lesion of individual nerves, those that belong simultaneously to different groups can also be affected. Thanks to the knowledge of their location and functions, it is possible not only to understand which nerve is disturbed, but also to localize the affected area. This becomes achievable through special techniques using high-tech equipment. For example, in ophthalmological practice, using modern technology, it is possible to find out the state of the fundus, the optic nerve, determine the field of view and foci of prolapse.

Good values ​​are revealed by carotid and vertebral angiography. But more detailed information can be obtained using computed tomography. With it, you can see individual nerve trunks and identify tumors and other changes in the auditory, optic and other nerves.

It became possible to study the trigeminal and auditory nerves thanks to the method of cortical somatosensory potentials. Also in this case, audiography and nystagmography are used.

The development of electromyography has expanded the possibilities for obtaining more detailed information about the cranial nerves. Now you can explore, for example, a reflex blinking response, spontaneous muscle activity during facial expressions and chewing, palate, and so on.

Let us dwell in more detail on each of the pairs of these nerves. There are 12 pairs of cranial nerves in total. A table where all of them are given is indicated at the end of the article. In the meantime, consider each of the pairs separately.

1 pair. Description

This includes from the group of sensitive. At the same time, receptor cells are scattered in the epithelium of the nasal cavity in the olfactory part. Thin nerve cell processes are concentrated in the olfactory filaments, which are olfactory nerves. From the nasal nerve enters the cranial cavity through the holes of the plate and ends in the bulb, from where the central olfactory pathways originate.

2 pairs. optic nerve

This pair includes the optic nerve, which belongs to the group of sensitive ones. The axons of neurons here exit through the cribriform plate from the eyeball in one trunk, which enters the cranial cavity. At the base of the brain, the fibers of these nerves converge on both sides to form the optic chiasm and tracts. The tracts go to the geniculate body and the thalamus of the pillow, after which the central visual path is directed to the occipital lobe of the brain.

3 pairs. motor nerve

The oculomotor (motor) nerve, made of fibers, runs from those nerves that are in the gray matter under the aqueduct of the brain. It passes to the base between the legs, after which it enters the orbit and innervates the eye muscles (except for the superior oblique and external straight lines, other cranial nerves, 12 pairs, are responsible for their innervation, the table indicating which clearly illustrates all of them together). This is due to the parasympathetic fibers contained in the nerve.

4 pairs. Block nerve

This pair includes (motor), originating from the nucleus under the aqueduct of the brain and coming to the surface in the region of the cerebral sail. In this part, a crossover, rounding of the leg and penetration into the orbit is obtained. This pair innervates the superior oblique muscle.

5th pair of 12 pairs of cranial nerves

The table continues with the trigeminal nerve, which is already mixed. In its trunk there are sensory and motor nuclei, and at the base - their roots and branches. Sensitive fibers originate from the cells of the trigeminal node, whose dendrites create peripheral branches that innervate the skin of the scalp in front, as well as the face, gums with teeth, the ocular conjunctiva, the mucous membranes of the nose, mouth, and tongue.
Motor fibers (from the root of the trigeminal nerve) connect with the mandibular nerve branch, pass and innervate the masticatory muscles.

6 pair. Abducens nerve

The next pair included in the 12 pairs of cranial nerves (the table refers to the group of motor nerves) includes a pair. It starts from the cell nuclei in the pons, penetrates to the base and moves forward to the orbital fissure from above and further to the orbit. It innervates the rectus eye muscle (external).

7 pair. facial nerve

This pair consists of the facial nerve (motor), created from the cell processes of the motor nucleus. The fibers begin their journey in the trunk at the bottom of the fourth ventricle, pass around the nucleus of the fourth nerve, descend to the base and exit into the pontocerebellar angle. Then he moves to the auditory opening, into the canal of the facial nerve. After the parotid gland, it divides into branches innervating the facial mimic and muscles, as well as a number of others. In addition, one branch extending from its trunk innervates a muscle located in the middle ear.

8 pair. Auditory nerve

The eighth pair of 12 pairs of cranial nerves (the table lists it among the sensory nerves) consists of the auditory, or vestibulocochlear nerve, which includes two parts: the vestibule and the cochlear. The cochlear part consists of dendrites and axons of the spiral node located in the bony cochlea. And the other part departs from the vestibular node at the bottom of the auditory canal. The nerve on both sides joins in the ear canal to the auditory nerve.

The fibers of the vestibular part end in those nuclei that are in the rhomboid fossa, and the cochlear part ends in the cochlear nuclei of the pons.

9 pair. Glossopharyngeal nerve

The table of cranial nerves continues with the ninth pair, which is represented. It includes sensory, motor, secretory and taste fibers. There are close connections with the vagus and intermediate nerves. Many nuclei of the nerve in question are located in the medulla oblongata. They are common with the tenth and twelfth pairs.

The nerve fibers of the pair are combined into a trunk that leaves the cranial cavity. For the posterior third of the palate and tongue, this is a taste and sensory nerve, for the inner ear and pharynx it is sensitive, for the pharynx it is motor, for the parotid gland it is secretory.

10 pair. Nervus vagus

Further, the table of cranial nerves continues with a pair, consisting of the vagus nerve, which is endowed with different functions. The trunk originates from roots in the medulla oblongata. After leaving the cranial cavity, the nerve innervates the striated muscles in the pharynx, as well as in the larynx, palate, trachea, bronchi and digestive organs.

Sensory fibers innervate the occipital region of the brain, the auditory canal from the outside, and other organs. Secretory fibers go to the stomach and pancreas, vasomotor - to the vessels, parasympathetic - to the heart.

11 pairs. Description of the accessory nerve

The accessory nerve presented in this pair consists of upper and lower sections. The first comes out of the motor nucleus of the medulla oblongata, and the second - from the nucleus in the horns of the spinal cord. The roots connect with each other and exit the skull along with the tenth pair. Some of them go to this vagus nerve.

It innervates the muscles - sternocleidomastoid and trapezius.

12 pair

The summary table of the cranial nerves ends with a pair with its nucleus located at the bottom of the medulla oblongata. After leaving the skull, it innervates the tongue muscles.

These are approximate diagrams of 12 pairs of cranial nerves. Let's summarize the above.

Look at the list of cranial nerves, 12 pairs. The table is the following.

Conclusion

This is the structure and function of these nerves. Each couple plays a different role. Each nerve is a part of a huge system and depends on it in the same way as the whole system depends on the functioning of individual nerves.

There are 13 pairs of cranial nerves (Fig. 222): zero pair - terminal nerve n. terminalis); I- olfactory (n. olfactorius); II - visual (n. opticus); III - oculomotor (n. oculomotorius); IV- block, (n. trochlearis); V- trigeminal (n. trigeminus); VI- outlet (n. abducens); VII - facial (n. facialis); VIII - vestibulocochlearis (n. vestibulocochlearis); IX- glossopharyngeal (n. glossopharyngeus); X- wandering (n. vagus); XI- additional (n. accessorius); XII- sublingual (n. hypoglossus).

DEVELOPMENT AND STRUCTURAL PRINCIPLES OF CRANIAL NERVE

Olfactory and optic nerves - specific nerves of the sense organs, develop from the forebrain and are its outgrowths. The rest of the cranial nerves differentiated from the spinal nerves and therefore are fundamentally similar in structure to them. Differentiation and transformation of the primary spinal nerves into cranial nerves are associated with the development of the sense organs and gill arches with their muscles, as well as with the reduction of myotomes in the head region (Fig. 223). However, none of the cranial nerves corresponds completely to the spinal nerves, since it is not composed of anterior and posterior roots, but only of one anterior or posterior one. Cranial nerves III, IV, VI pairs correspond to the anterior roots. Their nuclei are located ventrally, they innervate the muscles developed from the 3 anterior somites of the head. The remaining anterior roots are reduced.

The other cranial nerves V, VII, VIII, X, XI and XII pairs can be considered as homologues of the posterior roots. These nerves are associated with muscles that originate in the course of evolution from the muscles of the gill apparatus and developed in embryogenesis from the lateral plates of the mesoderm. In lower vertebrates, the nerves form two branches: anterior motor and posterior sensory.

Rice. 222. cranial nerves:

a - places of exit from the brain; b - places of exit from the skull;

1 - olfactory tract; 2 - optic nerve; 3 - oculomotor nerve; 4 - block nerve; 5 - trigeminal nerve; 6 - abducens nerve; 7 - facial nerve; 8 - vestibulocochlear nerve; 9 - oculomotor nerve; 10 - vagus nerve; 11 - accessory nerve; 12 - hypoglossal nerve; 13 - spinal cord; 14 - medulla oblongata; 15 - bridge; 16 - midbrain; 17 - diencephalon; 18 - olfactory bulb

In higher vertebrates, the posterior branch of the cranial nerves is usually reduced.

The X and XII cranial nerves have a complex origin, as they are formed during evolution by the fusion of several spinal nerves. In connection with the assimilation of the trunk metameres by the occipital region of the head, part of the spinal nerves moves cranially and enters the region of the medulla oblongata. Subsequently, the IX and XI cranial nerves are separated from a common source - the primary vagus nerve; they are, as it were, its branches (Table 14).

Rice. 222. The ending

Table 14 The ratio of somites of the head, branchial arches and cranial nerves with

their roots

Rice. 223.Cranial nerves of the human embryo. The gill arches are indicated by Arabic numerals, the nerves by Roman numerals:

1 - pre-ear somites; 2 - behind the ear somites; 3 - accessory nerve associated with the mesenchyme of the 5th gill arch; 4 - parasympathetic and visceral sensory fibers of the vagus nerve to the anterior and middle primary intestine; 5 - cardiac ledge; 6 - tympanic nerve (visceral sensory fibers to the middle ear and parasympathetic fibers to the parotid salivary gland); 7 - taste fibers to the anterior 2/3 of the tongue and parasympathetic fibers to the salivary glands; 8 - olfactory placode; 9 - mesenchyme of the head; 10 - submandibular node; 11 - eye glass; 12 - the rudiment of the lens; 13 - pterygopalatine node; 14 - ciliary knot; 15 - ear knot; 16 - ophthalmic nerve (sensitive to the orbit, nose and front of the head)

Rice. 224. Functional features of the cranial nerves: I - olfactory nerve; II - optic nerve; III - oculomotor: motor (external muscles of the eye, ciliary muscle and muscle that narrows the pupil); IV - trochlear nerve: motor (superior oblique muscle of the eye); V - trigeminal nerve: sensitive (face, paranasal sinuses, teeth); motor (chewing muscles); VI - abducens nerve: motor (lateral rectus muscle of the eye); VII - facial nerve: motor (facial muscles); intermediate nerve: sensitive (taste sensitivity); efferent (parasympathetic) (submandibular and sublingual salivary glands); VIII - vestibulocochlear nerve: sensitive (cochlea and vestibule); IX - glossopharyngeal nerve: sensitive (posterior third of the tongue, tonsil, pharynx, middle ear); motor (stylo-pharyngeal muscle); efferent (parasympathetic) (parotid salivary gland); X - vagus nerve: sensitive (heart, larynx, trachea, bronchi, lungs, pharynx, gastrointestinal tract, outer ear); motor (parasympathetic) (same area); XI - accessory nerve: motor (sternocleidomastoid and trapezius muscles); XII - hypoglossal nerve: motor (muscles of the tongue)

According to their functional affiliation, the cranial nerves are distributed as follows (Fig. 224). I, II and VIII pairs belong to the sensory nerves; III, IV, VI, XI and XII pairs are motor and contain fibers for striated muscles; V, VII, IX and X pairs are mixed nerves, as they contain both motor and sensory fibers. At the same time, parasympathetic fibers innervating smooth muscles and glandular epithelium pass through the III, VII, IX and X nerves. Along the cranial nerves and their branches, sympathetic fibers can join them, which greatly complicates the anatomy of the pathways of innervation of the organs of the head and neck.

The nuclei of the cranial nerves are located mainly in the rhomboid brain (V, VI, VII, VIII, IX, X, XI, XII pairs); in the cover of the legs of the brain, in the midbrain, there are nuclei of III and IV pairs, as well as one nucleus of the V pair; I and II pairs of cranial nerves are connected with the diencephalon (Fig. 225).

0 para - terminal nerves

Terminal nerve (null pair)(n. terminalis) are a pair of small nerves that are closely adjacent to the olfactory nerves. They were first discovered in lower vertebrates, but their presence has been shown in human fetuses and adults. They contain many unmyelinated fibers and associated small groups of bipolar and multipolar nerve cells. Each nerve runs along the medial side of the olfactory tract, their branches pierce the ethmoid plate of the ethmoid bone and branch out in the nasal mucosa. Centrally, the nerve is connected to the brain near the anterior perforated space and the septum pellucidum. Its function is unknown, but it is thought to be the head of the sympathetic nervous system, which extends to the blood vessels and glands of the nasal mucosa. There is also an opinion that this nerve is specialized for the perception of pheromones.

I pair - olfactory nerves

Olfactory nerve(n. olfactorius) educated 15-20 olfactory filaments (fila olfactoria), which consist of nerve fibers - processes of olfactory cells located in the mucous membrane of the upper part of the nasal cavity (Fig. 226). Olfactory threads

Rice. 225.The nuclei of the cranial nerves in the brain stem, rear view: 1 - oculomotor nerve; 2 - red core; 3 - motor nucleus of the oculomotor nerve; 4 - additional autonomous nucleus of the oculomotor nerve; 5 - the motor nucleus of the block nerve; 6 - block nerve; 7 - the motor nucleus of the trigeminal nerve; 8, 30 - trigeminal nerve and node; 9 - abducens nerve; 10 - the motor nucleus of the facial nerve; 11 - knee of the facial nerve; 12 - upper and lower salivary nuclei; 13, 24 - glossopharyngeal nerve; 14, 23 - vagus nerve; 15 - accessory nerve; 16 - double core; 17, 20 - dorsal nucleus of the vagus nerve; 18 - the nucleus of the hypoglossal nerve; 19 - spinal nucleus of the accessory nerve; 21 - the core of a single beam; 22 - spinal tract of the trigeminal nerve; 25 - nuclei of the vestibular nerve; 26 - nuclei of the cochlear nerve; 27 - vestibulocochlear nerve; 28 - facial nerve and knee node; 29 - the main sensory nucleus of the trigeminal nerve; 31 - mesencephalic trigeminal nucleus

Rice. 226. Olfactory nerve (diagram):

I - subcalcified field; 2 - partition field; 3 - anterior commissure; 4 - medial olfactory strip; 5 - parahippocampal gyrus; 6 - dentate gyrus; 7 - fringes of the hippocampus; 8 - hook; 9 - amygdala; 10 - anterior perforated substance; 11 - lateral olfactory strip; 12 - olfactory triangle; 13 - olfactory tract; 14 - ethmoid plate of the ethmoid bone; 15 - olfactory bulb; 16 - olfactory nerve; 17 - olfactory cells; 18 - mucous membrane of the olfactory region

enter the cranial cavity through a hole in the cribriform plate and end at the olfactory bulbs, which continue into olfactory tract (tractus olfactorius)(see fig. 222).

IIpair - optic nerves

optic nerve(n. opticus) consists of nerve fibers formed by the processes of multipolar nerve cells of the retina of the eyeball (Fig. 227). The optic nerve is formed in the posterior hemisphere of the eyeball and passes in the orbit to the optic canal, from where it exits into the cranial cavity. Here, in the precross sulcus, both optic nerves are connected, forming visual decussation (chiasma opticum). The continuation of the visual pathways is called the optic tract. (tractus opticus). At the optic chiasm, the medial group of nerve fibers of each nerve passes into the optic tract of the opposite side, and the lateral group continues into the corresponding optic tract. The visual tracts reach the subcortical visual centers (see Fig. 222).

Rice. 227. Optic nerve (diagram).

The fields of view of each eye are superimposed on one another; the dark circle in the center corresponds to the yellow spot; each quadrant has its own color: 1 - projection onto the retina of the right eye; 2 - optic nerves; 3 - optic chiasm; 4 - projection on the right geniculate body; 5 - visual tracts; 6, 12 - visual radiance; 7 - lateral cranked bodies; 8 - projection onto the cortex of the right occipital lobe; 9 - spur furrow; 10 - projection onto the cortex of the left occipital lobe; 11 - projection on the left geniculate body; 13 - projection on the retina of the left eye

III pair - oculomotor nerves

oculomotor nerve(n. oculomotorius) mainly motor, originates in the motor nucleus (nucleus nervi oculomotorii) midbrain and visceral autonomous accessory nuclei (nuclei visceralis accessorii n. oculomotorii). It comes to the base of the brain at the medial edge of the brain stem and goes forward in the upper wall of the cavernous sinus to the superior orbital fissure, through which it enters the orbit and is divided into upper branch (r. superior) - to the superior rectus muscle and the muscle that lifts the eyelid, and the lower branch (r. inferior)- to the medial and lower straight and lower oblique muscles (Fig. 228). A branch departs from the lower branch to the ciliary node, which is its parasympathetic root.

Rice. 228. Oculomotor nerve, lateral view: 1 - ciliary node; 2 - nasociliary root of the ciliary node; 3 - the upper branch of the oculomotor nerve; 4 - nasociliary nerve; 5 - ophthalmic nerve; 6 - oculomotor nerve; 7 - block nerve; 8 - accessory nucleus of the oculomotor nerve; 9 - motor nucleus of the oculomotor nerve; 10 - the nucleus of the trochlear nerve; 11 - abducens nerve; 12 - lateral rectus muscle of the eye; 13 - lower branch of the oculomotor nerve; 14 - medial rectus muscle of the eye; 15 - lower rectus muscle of the eye; 16 - oculomotor root of the ciliary node; 17 - lower oblique muscle of the eye; 18 - ciliary muscle; 19 - pupil dilator, 20 - pupil sphincter; 21 - upper rectus muscle of the eye; 22 - short ciliary nerves; 23 - long ciliary nerve

IVpara-trochlear nerves

Block nerve(n. trochlearis) motor, originates in the motor nucleus (nucleus n. trochlearis), located in the midbrain at the level of the inferior colliculus. It comes to the base of the brain outward from the bridge and continues forward in the outer wall of the cavernous sinus. Through the superior orbital fissure flows into the orbit and branches in the superior oblique muscle (Fig. 229).

Vpara - trigeminal nerves

Trigeminal nerve(n. trigeminus) is mixed and contains motor and sensory nerve fibers. Innervates chewing muscles, skin of the face and anterior part of the head, hard shell of the brain, as well as mucous membranes of the nasal and oral cavities, teeth.

The trigeminal nerve has a complex structure. It distinguishes

(Fig. 230, 231):

1) nuclei (one motor and three sensitive);

2) sensitive and motor roots;

3) trigeminal knot on a sensitive spine;

4) 3 main branches of the trigeminal nerve: ocular, maxillary and mandibular nerve.

Sensory nerve cells, the peripheral processes of which form the sensory branches of the trigeminal nerve, are located in trigeminal node, ganglion trigeminale. The trigeminal knot rests on trigeminal depression, inpressio trigeminalis, anterior surface of the pyramid of the temporal bone trigeminal cavity (cavum trigeminale), formed by the dura mater. The node is flat, crescent-shaped, 9-24 mm long (frontal size) and 3-7 mm wide (sagittal size). In people with a brachycephalic skull, the nodes are large, in the form of a straight line, while in dolichocephals they are small, in the form of an open circle.

The cells of the trigeminal node are pseudo-unipolar, i.e. give one process, which near the cell body is divided into central and peripheral. The central processes form sensitive root (radix sensorial) and through it they enter the brain stem, reaching the sensitive nuclei of the nerve: main nucleus (nucleus principalis nervi trigemini)- in the bridge and spinal nucleus (nucleus spinalis nervi trigemini) - in the lower part of the bridge, in the medulla oblongata and in the cervical segments of the spinal cord. In the midbrain is mesencephalic trigeminal nucleus (nucleus mesencephalicus

Rice. 229. Nerves of the orbit, dorsal view. (The upper wall of the orbit is removed): 1 - supraorbital nerve; 2 - muscle that lifts the upper eyelid; 3 - upper rectus muscle of the eye; 4 - lacrimal gland; 5 - lacrimal nerve; 6 - lateral rectus muscle of the eye; 7 - frontal nerve; 8 - maxillary nerve; 9 - mandibular nerve; 10 - trigeminal knot; 11 - a hint of the cerebellum; 12 - abducens nerve; 13, 17 - trochlear nerve; 14 - oculomotor nerve; 15 - optic nerve; 16 - ophthalmic nerve; 18 - nasociliary nerve; 19 - subblock nerve; 20 - upper oblique muscle of the eye; 21 - medial rectus muscle of the eye; 22 - supratrochlear nerve

Rice. 230. Trigeminal nerve (diagram):

1 - midbrain nucleus; 2 - the main sensitive core; 3 - spinal tract; 4 - facial nerve; 5 - mandibular nerve; 6 - maxillary nerve; 7 - ophthalmic nerve; 8 - trigeminal nerve and node; 9 - motor nucleus. Red solid line indicates motor fibers; solid blue line - sensitive fibers; blue dotted line - proprioceptive fibers; red dotted line - parasympathetic fibers; red dashed line - sympathetic fibers

nervi trigemini). This nucleus consists of pseudo-unipolar neurons and is believed to be related to the proprioceptive innervation of the muscles of the face and masticatory muscles.

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

Motor nerve fibers originate in motor nucleus of the nerve (nucleus motorius nervi trigemini), at the back of the bridge. These fibers leave the brain and form motor root (radix motoria). The exit point of the motor root from the brain and the entrance of the sensory one is located at the transition of the bridge to the middle cerebellar peduncle. Between the sensory and motor roots of the trigeminal nerve, there is often (in 25% of cases)

Rice. 231. Trigeminal nerve, lateral view. (The lateral wall of the orbit and part of the lower jaw are removed):

1 - trigeminal node; 2 - large stony nerve; 3 - facial nerve; 4 - mandibular nerve; 5 - ear-temporal nerve; 6 - lower alveolar nerve; 7 - lingual nerve; 8 - buccal nerve; 9 - pterygopalatine node; 10 - infraorbital nerve; 11 - zygomatic nerve; 12 - lacrimal nerve; 13 - frontal nerve; 14 - ophthalmic nerve; 15 - maxillary nerve

anastomotic connections, as a result of which a certain number of nerve fibers pass from one root to another.

The diameter of the sensitive root is 2.0-2.8 mm, it contains from 75,000 to 150,000 myelinated nerve fibers with a diameter mainly up to 5 microns. The thickness of the motor root is less - 0.8-1.4 mm. It contains from 6,000 to 15,000 myelinated nerve fibers with a diameter, usually more than 5 microns.

The sensory root with its trigeminal node and the motor root together make up the trunk of the trigeminal nerve with a diameter of 2.3-3.1 mm, containing from 80,000 to 165,000 myelinated nerve fibers. The motor root bypasses the trigeminal ganglion and enters the mandibular nerve.

Parasympathetic nerve nodes are connected with 3 main branches of the trigeminal nerve: the ciliary node - with the ophthalmic nerve, the pterygopalatine node - with the maxillary, ear, submandibular and sublingual nodes - with the mandibular nerves.

The general plan for dividing the main branches of the trigeminal nerve is as follows: each nerve (ophthalmic, maxillary and mandibular) gives off a branch to the dura mater; visceral branches - to the mucous membrane of the accessory sinuses, oral and nasal cavities and organs (lacrimal gland, eyeball, salivary glands, teeth); external branches, among which medial ones are distinguished - to the skin of the anterior regions of the face and lateral - to the skin of the lateral regions of the face.

ophthalmic nerve

ophthalmic nerve(n. ophthalmicus) is the first, thinnest branch of the trigeminal nerve. It is sensitive and innervates the skin of the forehead and the anterior part of the temporal and parietal regions, the upper eyelid, the back of the nose, and also partially the mucous membrane of the nasal cavity, the membranes of the eyeball and the lacrimal gland (Fig. 232).

The nerve is 2-3 mm thick, consists of 30-70 relatively small bundles and contains from 20,000 to 54,000 myelinated nerve fibers, mostly of small diameter (up to 5 microns). Upon departure from the trigeminal node, the nerve passes in the outer wall of the cavernous sinus, where it gives return shell (tentorial) branch (r. meningeus recurrens (tentorius) to the cerebellum. Near the superior orbital fissure, the optic nerve divides into 3 branches: lacrimal, frontal and nasociliary nerves.

Rice. 232. Nerves of the orbit, dorsal view. (Partially removed the muscle that lifts the upper eyelid, and the upper rectus and upper oblique muscles of the eye): 1 - long ciliary nerves; 2 - short ciliary nerves; 3, 11 - lacrimal nerve; 4 - ciliary knot; 5 - oculomotor root of the ciliary node; 6 - additional oculomotor root of the ciliary node; 7 - nasociliary root of the ciliary node; 8 - branches of the oculomotor nerve to the lower rectus muscle of the eye; 9, 14 - abducens nerve; 10 - lower branch of the oculomotor nerve; 12 - frontal nerve; 13 - ophthalmic nerve; 15 - oculomotor nerve; 16 - block nerve; 17 - branch of the cavernous sympathetic plexus; 18 - nasociliary nerve; 19 - the upper branch of the oculomotor nerve; 20 - posterior ethmoid nerve; 21 - optic nerve; 22 - anterior lattice nerve; 23 - subblock nerve; 24 - supraorbital nerve; 25 - supratrochlear nerve

1. Lacrimal nerve(n. lacrimalis) located near the outer wall of the orbit, where it receives connecting branch with the zygomatic nerve (r. communicans cum nervo zygomatico). Provides sensitive innervation of the lacrimal gland, as well as the skin of the upper eyelid and lateral canthus.

2.frontal nerve(n. frontalis) - the thickest branch of the optic nerve. Passes under the upper wall of the orbit and is divided into two branches: supraorbital nerve (n. supraorbital), going through the supraorbital notch to the skin of the forehead, and supratrochlear nerve (n. supratrochlearis), emerging from the orbit at its inner wall and innervating the skin of the upper eyelid and medial corner of the eye.

3.Nasociliary nerve(n. nasociliaris) lies in the orbit near its medial wall and, under the block of the superior oblique muscle, leaves the orbit in the form of a terminal branch - subtrochlear nerve (n. infratrochlearis), which innervates the lacrimal sac, conjunctiva and medial angle of the eye. In its course, the nasociliary nerve gives off the following branches:

1)long ciliary nerves (nn. ciliares longi) to the eyeball;

2)posterior ethmoidal nerve (n. ethmoidalis posterior) to the mucous membrane of the sphenoid sinus and the posterior cells of the ethmoid labyrinth;

3)anterior ethmoid nerve (n. ethmoidalis anterior) to the mucous membrane of the frontal sinus and nasal cavity (rr. nasales interni laterales et mediales) and to the skin of the tip and wing of the nose.

In addition, a connecting branch departs from the nasociliary nerve to the ciliary ganglion.

eyelash knot(ganglion ciliare)(Fig. 233), up to 4 mm long, lies on the lateral surface of the optic nerve, approximately on the border between the posterior and middle thirds of the length of the orbit. In the ciliary node, as in other parasympathetic nodes of the trigeminal nerve, there are parasympathetic multi-processed (multipolar) nerve cells, on which preganglionic fibers, forming synapses, switch to postganglionic ones. Sensory fibers transit through the node.

Connecting branches in the form of its roots approach the node:

1)parasympathetic (radix parasympathica (oculomotoria) gangliiciliaris) - from the oculomotor nerve;

2)sensitive (radix sensorial (nasociliaris) ganglii ciliaris) - from the nasopharyngeal nerve.

From the ciliary node departs from 4 to 40 short ciliary nerves (nn. ciliares breves), going inside the eyeball. They contain postganglionic parasympathetic fibers that innervate the ciliary muscle, sphincter and, to a lesser extent, the pupil dilator, as well as sensitive fibers to the membranes of the eyeball. (Sympathetic fibers to the dilator muscle are described below.)

Rice. 233. Ciliary knot (preparation of A.G. Tsybulkin). Impregnation with silver nitrate, clearing in glycerin. SW. x 12.

1 - ciliary knot; 2 - branch of the oculomotor nerve to the inferior oblique muscle of the eye; 3 - short ciliary nerves; 4 - ophthalmic artery; 5 - nasociliary root of the ciliary node; 6 - additional oculomotor roots of the ciliary node; 7 - oculomotor root of the ciliary node

maxillary nerve

maxillary nerve(n. maxillaries) - the second branch of the trigeminal nerve, sensitive. It has a thickness of 2.5-4.5 mm and consists of 25-70 small bundles containing from 30,000 to 80,000 myelinated nerve fibers, mostly of small diameter (up to 5 microns).

The maxillary nerve innervates the dura mater, the skin of the lower eyelid, the lateral angle of the eye, the anterior part of the temporal region, the upper part of the cheek, the wings of the nose, the skin and mucous membrane of the upper lip, the mucous membrane of the posterior and lower parts of the nasal cavity, the mucous membrane of the sphenoid sinus, and the palate. , teeth of the upper jaw. Upon exiting the skull through a round hole, the nerve enters the pterygopalatine fossa, passes from back to front and from inside to outside (Fig. 234). The length of the segment and its position in the fossa depend on the shape of the skull. With a brachycephalic skull, the length of the segment

the nerve in the fossa is 15-22 mm, it is located deep in the fossa - up to 5 cm from the middle of the zygomatic arch. Sometimes the nerve in the pterygopalatine fossa is covered by a bony crest. With a dolichocephalic skull, the length of the considered section of the nerve is 10-15 mm, it is located more superficially - up to 4 cm from the middle of the zygomatic arch.

Rice. 234. Maxillary nerve, lateral view. (The wall and contents of the orbit have been removed):

1 - lacrimal gland; 2 - zygomaticotemporal nerve; 3 - zygomaticofacial nerve; 4 - external nasal branches of the anterior ethmoid nerve; 5 - nasal branch; 6 - infraorbital nerve; 7 - anterior superior alveolar nerves; 8 - mucous membrane of the maxillary sinus; 9 - middle upper alveolar nerve; 10 - dental and gingival branches; 11 - upper dental plexus; 12 - infraorbital nerve in the canal of the same name; 13 - posterior superior alveolar nerves; 14 - nodal branches to the pterygopalatine node; 15 - large and small palatine nerves; 16 - pterygopalatine node; 17 - nerve of the pterygoid canal; 18 - zygomatic nerve; 19 - maxillary nerve; 20 - mandibular nerve; 21 - oval hole; 22 - round hole; 23 - meningeal branch; 24 - trigeminal nerve; 25 - trigeminal knot; 26 - ophthalmic nerve; 27 - frontal nerve; 28 - nasociliary nerve; 29 - lacrimal nerve; 30 - eyelash knot

Within the pterygo-palatine fossa, the maxillary nerve gives off meningeal branch (r. meningeus) to the dura mater and is divided into 3 branches:

1) nodal branches to the pterygopalatine node;

2) zygomatic nerve;

3) infraorbital nerve, which is a direct continuation of the maxillary nerve.

1. Nodal branches to the pterygopalatine node(rr. ganglionares ad ganglio pterygopalatinum)(1-7 in number) depart from the maxillary nerve at a distance of 1.0-2.5 mm from the round hole and go to the pterygopalatine node, giving sensory fibers to the nerves starting from the node. Some nodal branches bypass the node and join its branches.

Pterygopalatine node(ganglion pterygopalatinum) - formation of the parasympathetic part of the autonomic nervous system. The node is triangular in shape, 3-5 mm long, contains multipolar cells and has 3 roots:

1) sensitive - nodal branches;

2) parasympathetic - great stony nerve (n. petrosus major)(branch of the intermediate nerve), contains fibers to the glands of the nasal cavity, palate, lacrimal gland;

3) sympathetic - deep stony nerve (n. petrosus profundus) departs from the internal carotid plexus, contains postganglionic sympathetic nerve fibers from the cervical nodes. As a rule, the large and deep stony nerves are connected to the nerve of the pterygoid canal, passing through the canal of the same name at the base of the pterygoid process of the sphenoid bone.

Branches depart from the node, which include secretory and vascular (parasympathetic and sympathetic) and sensory fibers (Fig. 235):

1)orbital branches (rr. orbitales), 2-3 thin trunks penetrate through the inferior orbital fissure and then, together with the posterior ethmoid nerve, go through the small holes of the sphenoid-ethmoid suture to the mucous membrane of the posterior cells of the ethmoid labyrinth and sphenoid sinus;

2)posterior superior nasal branches (rr. nasales posteriores superiors)(8-14 in number) exit the pterygopalatine fossa through the sphenopalatine opening into the nasal cavity and are divided into two groups: lateral and medial (Fig. 236). Lateral branches

Rice. 235. Pterygopalatine node (diagram):

1 - upper salivary nucleus; 2 - facial nerve; 3 - knee of the facial nerve; 4 - large stony nerve; 5 - deep stony nerve; 6 - nerve of the pterygoid canal; 7 - maxillary nerve; 8 - pterygopalatine node; 9 - posterior superior nasal branches; 10 - infraorbital nerve; 11 - nasopalatine nerve; 12 - postganglionic autonomic fibers to the mucous membrane of the nasal cavity; 13 - maxillary sinus; 14 - posterior superior alveolar nerves; 15 - large and small palatine nerves; 16 - tympanic cavity; 17 - internal carotid nerve; 18 - internal carotid artery; 19 - upper cervical node of the sympathetic trunk; 20 - autonomous nuclei of the spinal cord; 21 - sympathetic trunk; 22 - spinal cord; 23 - medulla oblongata

(rr. nasales posteriores superiores laterales)(6-10), go to the mucous membrane of the posterior sections of the superior and middle turbinates and nasal passages, the posterior cells of the ethmoid bone, the upper surface of the choanae and the pharyngeal opening of the auditory tube. Medial branches (rr. nasales posteriores superiores mediales)(2-3), branch out in the mucous membrane of the upper part of the nasal septum. One of the medial branches nasopalatine nerve (n. nasopalatinus) - passes between the periosteum and the mucosa

Rice. 236. Nasal branches of the pterygopalatine node, view from the side of the nasal cavity: 1 - olfactory filaments; 2, 9 - nasopalatine nerve in the incisive canal; 3 - posterior superior medial nasal branches of the pterygopalatine node; 4 - posterior upper lateral nasal branches; 5 - pterygopalatine node; 6 - posterior lower nasal branches; 7 - small palatine nerve; 8 - large palatine nerve; 10 - nasal branches of the anterior ethmoid nerve

septum together with the posterior artery of the nasal septum forward, to the nasal opening of the incisive canal, through which it reaches the mucous membrane of the anterior part of the palate (Fig. 237). Forms a connection with the nasal branch of the superior alveolar nerve.

3) palatine nerves (nn. palatine) spread from the node through the large palatine canal, forming 3 groups of nerves:

Rice. 237. Sources of innervation of the palate, bottom view (soft tissues removed): 1 - nasopalatine nerve; 2 - large palatine nerve; 3 - small palatine nerve; 4 - soft palate

1)great palatine nerve (n. palatinus major) - the thickest branch, goes through the large palatine opening to the palate, where it breaks up into 3-4 branches, innervating most of the mucous membrane of the palate and its glands in the area from the fangs to the soft palate;

2)small palatine nerves (nn. palatini minores) enter the oral cavity through the small palatine openings and branch in the mucous membrane of the soft palate and the region of the palatine tonsil;

3)lower posterior nasal branches (rr. nasales posteriores inferiors) enter the greater palatine canal, leave it through small openings and enter the nasal cavity at the level of the inferior nasal concha, innervating the mucous membrane of the inferior concha, middle and lower nasal passages and maxillary sinus.

2. Zygomatic nerve(n. zygomaticus) branches off from the maxillary nerve within the pterygo-palatine fossa and penetrates through the inferior orbital fissure into the orbit, where it goes along the outer wall, gives off a connecting branch to the lacrimal nerve, containing secretory parasympathetic fibers to the lacrimal gland, enters the zygomatic-orbital foramen and inside the zygomatic bone is divided into two branches:

1)zygomaticofacial branch (r. zygomaticofacialis ), which exits through the zygomatic-facial opening to the anterior surface of the zygomatic bone; in the skin of the upper part of the cheek it gives off a branch to the area of ​​the outer canthus and a connecting branch to the facial nerve;

2)zygomaticotemporal branch (r. zygomaticotemporalis ), which exits the orbit through the opening of the zygomatic bone of the same name, perforates the temporal muscle and its fascia, and innervates the skin of the anterior part of the temporal and posterior parts of the frontal regions.

3. Infraorbital nerve(n. infraorbitalis ) is a continuation of the maxillary nerve and gets its name after the above-mentioned branches depart from it. The infraorbital nerve leaves the pterygopalatine fossa through the inferior orbital fissure, passes along the lower wall of the orbit along with the vessels of the same name in the infraorbital sulcus (in 15% of cases, there is a bone canal instead of the sulcus) and exits through the infraorbital foramen under the muscle that lifts the upper lip, dividing into terminal branches. The length of the infraorbital nerve is different: with brachycephaly, the nerve trunk is 20-27 mm, and with dolichocephaly - 27-32 mm. The position of the nerve in the orbit corresponds to the parasagittal plane drawn through the infraorbital foramen.

The branching can also be different: scattered, in which numerous thin nerves with many connections depart from the trunk, or main, with a small number of large nerves. On its way, the infraorbital nerve gives off the following branches:

1) superior alveolar nerves (nn. alveolares superiors) innervate the teeth and upper jaw (see Fig. 235). There are 3 groups of branches of the superior alveolar nerves:

1) posterior superior alveolar branches (rr. alveolares superiores posteriors) branch off from the infraorbital nerve, as a rule, in the pterygo-palatine fossa, 4-8 in number and are located along with the vessels of the same name along the surface of the tubercle of the upper jaw. Part of the most posterior nerves goes along the outer surface of the tubercle down to the alveolar process, the rest enter through the posterior superior alveolar openings into the alveolar canals. Branching together with other upper alveolar branches, they form the nervous superior dental plexus (plexus dentalis superior), which lies in the alveolar process of the upper jaw above the tops of the roots. The plexus is dense, wide-looped, stretched along the entire length of the alveolar process. depart from the plexus upper gums

high branches (rr. gingivales superiors) to the periodontium and periodontium in the area of ​​the upper molars and upper dental branches (rr. dentales superiors) - to the tops of the roots of large molars, in the pulp cavity of which they branch out. In addition, the posterior superior alveolar rami send fine nerves to the mucosa of the maxillary sinus;

2)middle upper alveolar branch (r. alveolaris superior) in the form of one or (rarely) two trunks, it branches off from the infraorbital nerve, more often in the pterygo-palatine fossa and (less often) within the orbit, passes in one of the alveolar canals and branches in the bone canals of the upper jaw as part of the superior dental plexus. It has connecting branches with posterior and anterior superior alveolar branches. Innervates through the upper gingival branches the periodontium and periodontium in the area of ​​​​the upper premolars and through the upper dental branches - the upper premolars;

3)anterior superior alveolar branches (rr. alveolares superiores anteriores) arise from the infraorbital nerve in the anterior part of the orbit, which they leave through the alveolar canals, penetrating into the anterior wall of the maxillary sinus, where they are part of the superior dental plexus. Upper gingival branches innervate the mucous membrane of the alveolar process and the walls of the alveoli in the area of ​​​​the upper canines and incisors, upper dental branches- upper canines and incisors. The anterior superior alveolar branches send a thin nasal branch to the mucosa of the anterior floor of the nasal cavity;

2)lower rami of the eyelids (rr. palpebrales inferiors) branches off from the infraorbital nerve at the exit from the infraorbital foramen, penetrates through the muscle that raises the upper lip, and, branching, innervates the skin of the lower eyelid;

3)external nasal branches (rr. nasales superiors) innervate the skin in the wing of the nose;

4)internal nasal branches (rr. nasales interni) approach the mucous membrane of the vestibule of the nasal cavity;

5)superior labial branches (rr. labiales superiors)(number 3-4) go between the upper jaw and the muscle that raises the upper lip, down; innervate the skin and mucous membrane of the upper lip to the corner of the mouth.

All of these external branches of the infraorbital nerve form connections with the branches of the facial nerve.

Mandibular nerve

Mandibular nerve(n. mandibularis) - the third branch of the trigeminal nerve is a mixed nerve and is formed by sensory nerve fibers coming from the trigeminal ganglion and motor fibers of the motor root (Fig. 238, 239). The thickness of the nerve trunk ranges from 3.5 to 7.5 mm, and the length of the extracranial part of the trunk is 0.5-2.0 cm. The nerve consists of 30-80 fiber bundles, including from 50,000 to 120,000 myelinated nerve fibers.

The mandibular nerve carries out sensitive innervation of the hard shell of the brain, the skin of the lower lip, chin, lower cheek, anterior part of the auricle and external auditory canal, part of the surface of the tympanic membrane, buccal mucosa, floor of the mouth and the anterior two-thirds of the tongue, teeth of the lower jaw , as well as the motor innervation of all the masticatory muscles, the maxillofacial muscle, the anterior belly of the digastric muscle and the muscles that strain the eardrum and the palatine curtain.

From the cranial cavity, the mandibular nerve exits through the foramen ovale and enters the infratemporal fossa, where it divides near the exit point into a number of branches. Branching of the mandibular nerve is possible or loose type(more often with dolichocephaly) - the nerve splits into many branches (8-11), or along trunk type(more often with brachycephaly) with branching into a small number of trunks (4-5), each of which is common to several nerves.

Three nodes of the autonomic nervous system are associated with the branches of the mandibular nerve: ear(ganglion oticum);submandibular(ganglion submandibulare);sublingual(ganglion sublinguale). From the nodes go postganglionic parasympathetic secretory fibers to the salivary glands.

The mandibular nerve gives off a number of branches.

1.Meningeal branch(r. meningeus) passes through the foramen spinosa together with the middle meningeal artery into the cranial cavity, where it branches into the dura mater.

2.chewing nerve(n. massetericus), predominantly motor, often (especially with the main form of branching of the mandibular nerve) has a common origin with other nerves of the masticatory muscles. Passes outwards over the upper edge of the lateral pterygoid muscle, then through the notch of the lower jaw and is introduced into the masticatory muscle. Before entering the muscle sends a thin branch

Rice. 238. Mandibular nerve, left view. (Mandibular branch removed):

1 - ear-temporal nerve; 2 - middle meningeal artery; 3 - superficial temporal artery; 4 - facial nerve; 5 - maxillary artery; 6 - lower alveolar nerve; 7 - maxillofacial nerve; 8 - submandibular node; 9 - internal carotid artery; 10 - mental nerve; 11 - medial pterygoid muscle; 12 - lingual nerve; 13 - drum string; 14 - buccal nerve; 15 - nerve to the lateral pterygoid muscle; 16 - pterygopalatine node; 17 - infraorbital nerve; 18 - maxillary nerve; 19 - zygomaticofacial nerve; 20 - nerve to the medial pterygoid muscle; 21 - mandibular nerve; 22 - chewing nerve; 23 - deep temporal nerves; 24 - zygomaticotemporal nerve

Rice. 239. Mandibular nerve, medial view: 1 - motor root; 2 - sensitive root; 3 - large stony nerve; 4 - small stony nerve; 5 - nerve to the muscle straining the eardrum; 6, 12 - drum string; 7 - ear-temporal nerve; 8 - lower alveolar nerve; 9 - maxillofacial nerve; 10 - lingual nerve; 11 - medial pterygoid nerve; 13 - ear knot; 14 - nerve to the muscle that strains the palatine curtain; 15 - mandibular nerve; 16 - maxillary nerve; 17 - ophthalmic nerve; 18 - trigeminal knot

to the temporomandibular joint, providing its sensitive innervation.

3.Deep temporal nerves(nn. temporales profundi), motor, pass along the outer base of the skull outward, bend around the infratemporal crest and enter the temporal muscle from its inner surface in the anterior (n. temporalis profundus anterior) and back (n. temporalis profundus posterior) departments.

4.Lateral pterygoid nerve(n. pterygoideus lateralis) motor, usually departs in a common trunk with the buccal nerve, approaches the muscle of the same name, in which it branches.

5.medial pterygoid nerve(n. pterygoideus medialis), mainly motor. It passes through the ear node or is adjacent to its surface and follows forward and downward to the inner surface of the muscle of the same name, into which it penetrates near its upper edge. In addition, near the ear node, he gives nerve to the muscle that strains the palatine curtain (n. musculi tensoris veli palatine), nerve to the muscle that strains the eardrum (n. musculi tensoris tympani), and a connecting branch to the node.

6.buccal nerve(n. buccalis), sensitive, penetrates between the two heads of the lateral pterygoid muscle and goes along the inner surface of the temporal muscle, spreading further along with the buccal vessels along the outer surface of the buccal muscle to the corner of the mouth. On its way, it gives off thin branches that pierce the buccal muscle and innervate the mucous membrane of the cheek (up to the gums of the 2nd premolar and 1st molar) and branches to the skin of the cheek and corner of the mouth. Forms a connecting branch with a branch of the facial nerve and with the ear node.

7.Auriculotemporal nerve(n. auriculotemporalis ), sensitive, starts from the posterior surface of the mandibular nerve with two roots covering the middle meningeal artery, which then join into a common trunk. Receives from the ear node a connecting branch containing parasympathetic fibers. Near the neck of the articular process of the lower jaw, the auricular-temporal nerve goes up and through the parotid salivary gland exits into the temporal region, where it branches into terminal branches - superficial temporal (rr. temporales superficiales). On its way, the ear-temporal nerve gives off the following branches:

1)articular (rr. articulares), to the temporomandibular joint;

2)parotid (rr. parotidei), to the parotid salivary gland. These branches contain, in addition to sensitive, parasympathetic secretory fibers from the ear node;

3)nerve of the external auditory canal (n. meatus acustuci externi), to the skin of the external auditory canal and eardrum;

4)anterior ear nerves (nn. auriculares anteriores), to the skin of the anterior part of the auricle and the middle part of the temporal region.

8.lingual nerve(n. lingualis), sensitive. It originates from the mandibular nerve near the foramen ovale and is located between the pterygoid muscles anterior to the inferior alveolar nerve. At the upper edge of the medial pterygoid muscle or slightly lower, it joins the nerve drum string (chorda tympani), which is a continuation of the intermediate nerve.

As part of the drum string, secretory fibers are included in the lingual nerve, following to the submandibular and hypoglossal nerve nodes, and taste fibers to the papillae of the tongue. Further, the lingual nerve passes between the inner surface of the lower jaw and the medial pterygoid muscle, above the submandibular salivary gland along the outer surface of the hyoid-lingual muscle to the lateral surface of the tongue. Between the hyoid-lingual and genio-lingual muscles, the nerve breaks up into terminal lingual branches (rr. linguales).

Along the course of the nerve, connecting branches form with the hypoglossal nerve and the tympanic string. In the oral cavity, the lingual nerve gives off the following branches:

1)branches to the isthmus of the pharynx (rr. isthmi faucium), innervating the mucous membrane of the pharynx and the posterior part of the floor of the mouth;

2)hypoglossal nerve (n. sublingualis) departs from the lingual nerve at the posterior edge of the hyoid node in the form of a thin connecting branch and extends forward along the lateral surface of the hyoid salivary gland. Innervates the mucous membrane of the bottom of the mouth, gums and sublingual salivary gland;

3)lingual branches (rr. linguales) pass along with the deep artery and veins of the tongue through the muscles of the tongue forward and end in the mucous membrane of the apex of the tongue and its body to the boundary line. As part of the lingual branches, taste fibers pass to the papillae of the tongue, passing from the drum string.

9. inferior alveolar nerve(n. alveolaris inferior) mixed. This is the largest branch of the mandibular nerve. Its trunk lies between the pterygoid muscles behind and lateral to the lingual nerve, between the mandible and the sphenomandibular ligament. The nerve enters, together with the vessels of the same name, into the mandibular canal, where it gives off multiple branches that anastomose with each other and form inferior dental plexus (plexus dentalis inferior)(in 15% of cases), or directly the lower dental and gingival branches. It leaves the canal through the mental foramen, dividing before entering the mental nerve and the incisive branch. Gives the following branches:

1) maxillofacial nerve (n. mylohyoides) arises near the entrance of the lower alveolar nerve into the mandibular foramen, is located in the sulcus of the same name of the branch of the lower jaw and goes to the maxillohyoid muscle and the anterior belly of the digastric muscle;

2)lower dental and gingival branches (rr. dentales et gingivales inferiors) originate from the inferior alveolar nerve in the mandibular canal; innervate the gums, alveoli of the alveolar part of the jaw and teeth (premolars and molars);

3)mental nerve (n. mentalis) is a continuation of the trunk of the lower alveolar nerve at the exit through the mental foramen from the mandibular canal; here the nerve is fan-shaped into 4-8 branches, among which there are chin (rr. mentales), to the skin of the chin and lower labials (rr. labials inferiors), to the skin and mucous membrane of the lower lip.

ear knot(ganglion oticum) - rounded flattened body with a diameter of 3-5 mm; located under the foramen ovale on the posteromedial surface of the mandibular nerve (Fig. 240, 241). A small stony nerve (from the glossopharyngeal) approaches it, bringing preganglionic parasympathetic fibers. A number of connecting branches depart from the node:

1) to the ear-temporal nerve, which receives postganglionic parasympathetic secretory fibers, which then go as part of the parotid branches to the parotid salivary gland;

2) to the buccal nerve, through which the postganglionic parasympathetic secretory fibers reach the small salivary glands of the oral cavity;

3) to the drum string;

4) to the pterygopalatine and trigeminal nodes.

Submandibular knot(ganglion submandibulare)(size 3.0-3.5 mm) is located under the trunk of the lingual nerve and is associated with it nodal branches (rr. ganglionares)(Fig. 242, 243). These branches lead to the node and terminate in it the preganglionic parasympathetic fibers of the tympanic string. Branches leaving the node innervate the submandibular and sublingual salivary glands.

Sometimes (up to 30% of cases) there is a separate sublingual node(ganglion sublingualis).

VI pair - abducens nerves

Abducens nerve (n. abducens - motor. Abducens nucleus (nucleus n. abducentis) located in the anterior part of the bottom of the IV ventricle. The nerve exits the brain at the posterior edge of the bridge, between it and the pyramid of the medulla oblongata, and soon outside the back of the Turkish saddle enters the cavernous sinus, where it is located along the outer surface of the internal carotid artery (Fig. 244). Further

Rice. 240. Autonomous nodes of the head, view from the medial side: 1 - nerve of the pterygoid canal; 2 - maxillary nerve; 3 - ophthalmic nerve; 4 - ciliary knot; 5 - pterygopalatine node; 6 - large and small palatine nerves; 7 - submandibular node; 8 - facial artery and nerve plexus; 9 - cervical sympathetic trunk; 10, 18 - internal carotid artery and nerve plexus; 11 - upper cervical node of the sympathetic trunk; 12 - internal carotid nerve; 13 - drum string; 14 - ear-temporal nerve; 15 - small stony nerve; 16 - ear knot; 17 - mandibular nerve; 19 - sensitive root of the trigeminal nerve; 20 - motor root of the trigeminal nerve; 21 - trigeminal knot; 22 - large stony nerve; 23 - deep stony nerve

Rice. 241. The ear node of an adult (preparations of A.G. Tsybulkin): a - macromicropreparation, stained with Schiff's reagent, SW. x12: 1 - mandibular nerve in the foramen ovale (medial surface); 2 - ear knot; 3 - sensitive root of the ear node; 4 - connecting branches to the buccal nerve; 5 - additional ear nodes; 6 - connecting branches to the ear-temporal nerve; 7 - middle meningeal artery; 8 - small stony nerve; b - histotopogram, stained with hematoxylin-eosin, SW. X 10X 7

penetrates through the superior orbital fissure into the orbit and follows forward over the oculomotor nerve. Innervates the external rectus muscle of the eye.

VII pair - facial nerves

facial nerve(n. facialis) develops in connection with the formations of the second gill arch (see Fig. 223), so it innervates all the muscles of the face (mimic). The nerve is mixed, including motor fibers from its efferent nucleus, as well as sensory and autonomic (gustatory and secretory) fibers belonging to a closely related facial intermediate nerve(n. intermedins).

Motor nucleus of the facial nerve(nucleus n. facialis) located at the bottom of the IV ventricle, in the lateral region of the reticular formation. The facial nerve root emerges from the brain along with the intermediate nerve root anterior to the vestibulocochlear nerve, between

Rice. 242. Submandibular node, lateral view. (Most of the lower jaw removed):

1 - mandibular nerve; 2 - deep temporal nerves; 3 - buccal nerve; 4 - lingual nerve; 5 - submandibular node; 6 - submandibular salivary gland; 7 - maxillofacial nerve; 8 - lower alveolar nerve; 9 - drum string; 10 - ear-temporal nerve

the posterior margin of the pons and the olive of the medulla oblongata. Further, the facial and intermediate nerves enter the internal auditory opening and enter the canal of the facial nerve. Here, both nerves form a common trunk, making two turns corresponding to the bends of the canal (Fig. 245, 246).

First, the common trunk is located horizontally, heading anteriorly and laterally above the tympanic cavity. Then, according to the bend of the facial canal, the barrel turns at a right angle back, forming a knee (geniculum n. facialis) and knee joint (ganglion geniculi), belonging to the intermediate nerve. Having passed over the tympanic cavity, the trunk makes a second downward turn, located behind the cavity of the middle ear. In this area, the branches of the intermediate nerve depart from the common trunk, the facial nerve exits the canal

Rice. 243. Submandibular node (drug A.G. Tsybulkin): 1 - lingual nerve; 2 - nodal branches; 3 - submandibular node; 4 - glandular branches; 5 - submandibular salivary gland; 6 - branch of the submandibular node to the sublingual gland; 7 - submandibular duct

Rice. 244.Nerves of the oculomotor apparatus (diagram):

1 - superior oblique muscle of the eye; 2 - upper rectus muscle of the eye; 3 - block nerve; 4 - oculomotor nerve; 5 - lateral rectus muscle of the eye; 6 - lower rectus muscle of the eye; 7 - abducens nerve; 8 - lower oblique muscle of the eye; 9 - medial rectus muscle of the eye

Rice. 245. Facial nerve (diagram):

1 - internal carotid plexus; 2 - knee assembly; 3 - facial nerve; 4 - facial nerve in the internal auditory canal; 5 - intermediate nerve; 6 - the motor nucleus of the facial nerve; 7 - upper salivary nucleus; 8 - the core of a single path; 9 - occipital branch of the posterior auricular nerve; 10 - branches to the ear muscles; 11 - posterior ear nerve; 12 - nerve to the stirrup muscle; 13 - stylomastoid opening; 14 - tympanic plexus; 15 - tympanic nerve; 16 - glossopharyngeal nerve; 17 - posterior belly of the digastric muscle; 18 - stylohyoid muscle; 19 - drum string; 20 - lingual nerve (from the mandibular); 21 - submandibular salivary gland; 22 - sublingual salivary gland; 23 - submandibular node; 24 - pterygopalatine node; 25 - ear knot; 26 - nerve of the pterygoid canal; 27 - small stony nerve; 28 - deep stony nerve; 29 - large stony nerve

Rice. 246. Intraosseous part of the facial nerve trunk:

1 - large stony nerve; 2 - knot of the knee of the facial nerve; 3 - front channel; 4 - tympanic cavity; 5 - drum string; 6 - hammer; 7 - anvil; 8 - semicircular canaliculi; 9 - spherical bag; 10 - elliptical bag; 11 - node vestibule; 12 - internal auditory meatus; 13 - nuclei of the cochlear nerve; 14 - lower cerebellar peduncle; 15 - nuclei of the vestibular nerve; 16 - medulla oblongata; 17 - vestibulocochlear nerve; 18 - motor portion of the facial nerve and intermediate nerve; 19 - cochlear nerve; 20 - vestibular nerve; 21 - spiral ganglion

Rice. 247. Parotid plexus of the facial nerve:

a - main branches of the facial nerve, right side view: 1 - temporal branches; 2 - zygomatic branches; 3 - parotid duct; 4 - buccal branches; 5 - marginal branch of the lower jaw; 6 - cervical branch; 7 - digastric and stylohyoid branches;

8 - the main trunk of the facial nerve at the exit from the stylomastoid foramen;

9- posterior ear nerve; 10 - parotid salivary gland;

b - facial nerve and parotid gland in a horizontal section: 1 - medial pterygoid muscle; 2 - branch of the lower jaw; 3 - chewing muscle; 4 - parotid salivary gland; 5 - mastoid process; 6 - the main trunk of the facial nerve;

c - three-dimensional diagram of the relationship between the facial nerve and the parotid salivary gland: 1 - temporal branches; 2 - zygomatic branches; 3 - buccal branches; 4 - marginal branch of the lower jaw; 5 - cervical branch; 6 - lower branch of the facial nerve; 7 - digastric and stylohyoid branches of the facial nerve; 8 - the main trunk of the facial nerve; 9 - posterior ear nerve; 10 - the upper branch of the facial nerve

through the stylomastoid opening and soon enters the parotid salivary gland. The length of the trunk of the extracranial part of the facial nerve ranges from 0.8 to 2.3 cm (usually 1.5 cm), and the thickness is from 0.7 to 1.4 mm; the nerve contains 3500-9500 myelinated nerve fibers, among which thick ones predominate.

In the parotid salivary gland, at a depth of 0.5-1.0 cm from its outer surface, the facial nerve divides into 2-5 primary branches, which are divided into secondary ones, forming parotid plexus (plexus intraparotidus)(Fig. 247).

There are two forms of the external structure of the parotid plexus: reticular and main. At network form the nerve trunk is short (0.8-1.5 cm), in the thickness of the gland it is divided into many branches that have multiple connections with each other, as a result of which a narrow-loop plexus is formed. There are multiple connections with the branches of the trigeminal nerve. At trunk form the nerve trunk is relatively long (1.5-2.3 cm), divided into two branches (upper and lower), which give rise to several secondary branches; there are few connections between the secondary branches, the plexus is wide-looped (Fig. 248).

On its way, the facial nerve gives off branches when passing through the canal, as well as when leaving it. Inside the channel, a number of branches depart from it:

1.Greater stony nerve(n. petrosus major) originates near the node of the knee, leaves the canal of the facial nerve through the cleft of the canal of the large stony nerve and passes along the sulcus of the same name to the ragged foramen. Having penetrated through the cartilage to the outer base of the skull, the nerve connects to the deep petrosal nerve, forming pterygoid canal nerve (n. canalis pterygoidei), entering the pterygoid canal and reaching the pterygopalatine node.

The large stony nerve contains parasympathetic fibers to the pterygopalatine ganglion, as well as sensory fibers from the cells of the geniculate ganglion.

2.Stapes nerve(n. stapedius)- a thin trunk, branches off in the canal of the facial nerve at the second turn, penetrates the tympanic cavity, where it innervates the stapedius muscle.

3.drum string(chorda tympani) is a continuation of the intermediate nerve, separates from the facial nerve in the lower part of the canal above the stylomastoid foramen and enters through the tubule of the tympanic string into the tympanic cavity, where it lies under the mucous membrane between the long leg of the anvil and the handle of the malleus. Through

Rice. 248. Differences in the structure of the facial nerve:

a - network structure; b - main structure;

1 - facial nerve; 2 - chewing muscle

stony-tympanic fissure, the tympanic string goes to the outer base of the skull and merges with the lingual nerve in the infratemporal fossa.

At the point of intersection with the lower alveolar nerve, the drum string gives a connecting branch with the ear node. The string tympani consists of preganglionic parasympathetic fibers to the submandibular ganglion and taste-sensitive fibers to the anterior two-thirds of the tongue.

4. Connecting branch with tympanic plexus(r. communicans cum plexus tympanico) - thin branch; starts from the node of the knee or from the large stony nerve, passes through the roof of the tympanic cavity to the tympanic plexus.

Upon exiting the canal, the following branches depart from the facial nerve.

1.Posterior ear nerve(n. auricularis posterior) departs from the facial nerve immediately after exiting the stylomastoid foramen, goes back and up the anterior surface of the mastoid process, dividing into two branches: ear (r. auricularis), innervates the posterior ear muscle, and occipital (r. occipitalis), innervates the occipital belly of the supracranial muscle.

2.digastric branch(r. digasricus) arises slightly below the ear nerve and, going down, innervates the posterior belly of the digastric muscle and the stylohyoid muscle.

3.Connecting branch with glossopharyngeal nerve(r. communicans cum nervo glossopharyngeo) branches off near the stylomastoid foramen and extends anteriorly and down the stylopharyngeal muscle, connecting with the branches of the glossopharyngeal nerve.

Branches of the parotid plexus:

1.Temporal branches(rr. temporales)(2-4 in number) go up and are divided into 3 groups: anterior, innervating the upper part of the circular muscle of the eye, and the muscle wrinkling the eyebrow; medium, innervating the frontal muscle; back, innervating the vestigial muscles of the auricle.

2.zygomatic branches(rr. zygomatici)(number 3-4) spread forward and upward to the lower and lateral parts of the circular muscle of the eye and the zygomatic muscle, which innervate.

3.buccal branches(rr. buccales)(number 3-5) go horizontally anteriorly along the outer surface of the masticatory muscle and supply the branches of the muscle in the circumference of the nose and mouth.

4.Marginal branch of the lower jaw(r. marginalis mandibularis) runs along the edge of the lower jaw and innervates the muscles that lower the corner of the mouth and lower lip, the chin muscle and the muscle of laughter.

5. cervical branch(r. colli) descends to the neck, connects with the transverse nerve of the neck and innervates m. platysma.

Intermediate nerve(n. intermediate) consists of preganglionic parasympathetic and sensory fibers. Sensitive unipolar cells are located in the knee node. The central processes of the cells ascend as part of the nerve root and terminate in the nucleus of the solitary pathway. Peripheral processes of sensory cells go through the tympanic string and the large stony nerve to the mucous membrane of the tongue and soft palate.

Secretory parasympathetic fibers originate in the superior salivary nucleus in the medulla oblongata. The root of the intermediate nerve exits the brain between the facial and vestibulocochlear nerves, joins the facial nerve and goes in the canal of the facial nerve. The fibers of the intermediate nerve leave the trunk of the facial, passing into the tympanic string and the large stony nerve, reach the submandibular, hyoid and pterygopalatine nodes.

Questions for self-control

1. What cranial nerves are mixed?

2. What cranial nerves develop from the forebrain?

3. What nerves innervate the external muscles of the eye?

4. What branches depart from the optic nerve? Specify their areas of innervation.

5. What nerves innervate the upper teeth? Where do these nerves come from?

6. What branches of the mandibular nerve do you know?

7. What nerve fibers pass through the drum string?

8. What branches depart from the facial nerve inside its canal? What do they innervate?

9. What branches depart from the facial nerve in the region of the parotid plexus? What do they innervate?

VIII pair - vestibulocochlear nerves

Vestibulocochlear nerve(n. vestibulocochlearis)- sensitive, consists of two functionally different parts: vestibular and cochlear(see fig. 246).

Vestibular nerve (n. vestibularis) conducts impulses from the static apparatus of the vestibule and semicircular canals of the labyrinth of the inner ear. Cochlear nerve (n. cochlearis) provides the transmission of sound stimuli from the spiral organ of the cochlea. Each part of the nerve has its own sensory nodes containing bipolar nerve cells: the vestibulum - vestibulum(ganglion vestibulare) located at the bottom of the internal auditory canal; cochlear part - cochlear node (cochlear node), ganglion cochleare (ganglion spirale cochleare), which is in the snail.

The vestibular node is elongated, it distinguishes two parts: upper (pars superior) and lower (pars inferior). The peripheral processes of the cells of the upper part form the following nerves:

1)elliptic saccular nerve (n. utricularis), to the cells of the elliptical sac of the vestibule of the cochlea;

2)anterior ampullar nerve (n. ampularis anterior), to the cells of the sensitive strips of the anterior membranous ampulla of the anterior semicircular canal;

3)lateral ampullar nerve (n. ampularis lateralis), to the lateral membranous ampulla.

From the lower part of the vestibular node, peripheral processes of cells go in the composition spherical saccular nerve (n. saccularis)

Rice. 249. Vestibulocochlear nerve:

1 - elliptical saccular nerve; 2 - anterior ampullar nerve; 3 - posterior ampullar nerve; 4 - spherical-saccular nerve; 5 - lower branch of the vestibular nerve; 6 - the upper branch of the vestibular nerve; 7 - vestibular node; 8 - root of the vestibular nerve; 9 - cochlear nerve

Rice. 250. Glossopharyngeal nerve:

1 - tympanic nerve; 2 - knee of the facial nerve; 3 - lower salivary nucleus; 4 - double core; 5 - the core of a single path; 6 - the core of the spinal cord; 7, 11 - glossopharyngeal nerve; 8 - jugular opening; 9 - connecting branch to the ear branch of the vagus nerve; 10 - upper and lower nodes of the glossopharyngeal nerve; 12 - vagus nerve; 13 - upper cervical node of the sympathetic trunk; 14 - sympathetic trunk; 15 - sinus branch of the glossopharyngeal nerve; 16 - internal carotid artery; 17 - common carotid artery; 18 - external carotid artery; 19 - tonsil, pharyngeal and lingual branches of the glossopharyngeal nerve (pharyngeal plexus); 20 - stylo-pharyngeal muscle and nerve to it from the glossopharyngeal nerve; 21 - auditory tube; 22 - tubal branch of the tympanic plexus; 23 - parotid salivary gland; 24 - ear-temporal nerve; 25 - ear knot; 26 - mandibular nerve; 27 - pterygopalatine node; 28 - small stony nerve; 29 - nerve of the pterygoid canal; 30 - deep stony nerve; 31 - large stony nerve; 32 - carotid-tympanic nerves; 33 - stylomastoid opening; 34 - tympanic cavity and tympanic plexus

to the auditory spot of the sac and in the composition posterior ampullar nerve (n. ampularis posterior) to the posterior membranous ampulla.

The central processes of the cells of the vestibular ganglion form vestibular (upper) spine, which exits through the internal auditory opening behind the facial and intermediate nerves and enters the brain near the exit of the facial nerve, reaching 4 vestibular nuclei in the bridge: medial, lateral, superior and inferior.

From the cochlear node, the peripheral processes of its bipolar nerve cells go to the sensitive epithelial cells of the spiral organ of the cochlea, forming together the cochlear part of the nerve. The central processes of the cochlear ganglion cells form cochlear (lower) spine, going along with the upper root to the brain to the dorsal and ventral cochlear nuclei.

IX pair - glossopharyngeal nerves

Glossopharyngeal nerve(n. glossopharyngeus) - nerve of the third gill arch, mixed. It innervates the mucous membrane of the posterior third of the tongue, the palatine arches, the pharynx and the tympanic cavity, the parotid salivary gland and the stylo-pharyngeal muscle (Fig. 249, 250). There are 3 types of nerve fibers in the composition of the nerve:

1) sensitive;

2) motor;

3) parasympathetic.

Sensitive fibers - outgrowths of afferent cells top and bottom nodes (ganglia superior et inferior). The peripheral processes follow as part of the nerve to the organs where they form receptors, the central ones go to the medulla oblongata, to the sensitive the nucleus of the solitary path (nucleus tractus solitarii).

motor fibers originate from nerve cells in common with the vagus nerve double nucleus (nucleus ambiguous) and pass as part of the nerve to the stylo-pharyngeal muscle.

Parasympathetic fibers originate in the autonomic parasympathetic lower salivary nucleus (nucleus salivatorius superior), which is located in the medulla oblongata.

The glossopharyngeal nerve root exits the medulla oblongata behind the exit site of the vestibulocochlear nerve and, together with the vagus nerve, leaves the skull through the jugular foramen. In this hole, the nerve has the first expansion - top knot (ganglion superior), and at the exit from the hole - the second expansion - bottom node (ganglion inferior).

Outside the skull, the glossopharyngeal nerve lies first between the internal carotid artery and the internal jugular vein, and then in a gentle arc it goes around the back and outside of the stylo-pharyngeal muscle and comes from the inside of the hyoid-lingual muscle to the root of the tongue, dividing into terminal branches.

Branches of the glossopharyngeal nerve.

1.Tympanic nerve(n. tympanicus) branches off from the lower node and passes through the tympanic canaliculus into the tympanic cavity, where it forms together with the carotid-tympanic nerves tympanic plexus (plexus tympanicus). The tympanic plexus innervates the mucous membrane of the tympanic cavity and the auditory tube. The tympanic nerve leaves the tympanic cavity through its superior wall as small stony nerve (n. petrosus minor) and goes to the ear node. Preganglionic parasympathetic secretory fibers, suitable as part of the small stony nerve, are interrupted in the ear node, and postganglionic secretory fibers enter the ear-temporal nerve and reach the parotid salivary gland in its composition.

2.Branch of the stylo-pharyngeal muscle(r. m. stylopharyngei) goes to the muscle of the same name and the mucous membrane of the pharynx.

3.sinus branch(r. sinus carotici) sensitive, branches in the sleepy glomus.

4.almond branches(rr. tonsillares) are sent to the mucous membrane of the palatine tonsil and arches.

5.Pharyngeal branches(rr. pharyngei)(3-4 in number) approach the pharynx and, together with the pharyngeal branches of the vagus nerve and the sympathetic trunk, form on the outer surface of the pharynx pharyngeal plexus (plexus pharyngealis). Branches depart from it to the muscles of the pharynx and to the mucous membrane, which, in turn, form intramural nerve plexuses.

6.lingual branches(rr. linguales) - terminal branches of the glossopharyngeal nerve: contain sensitive taste fibers to the mucous membrane of the posterior third of the tongue.

X pair - vagus nerves

Nervus vagus(n. vagus), mixed, develops in connection with the fourth or fifth gill arches, is widely distributed due to which it got its name. It innervates the respiratory organs, organs of the digestive system (up to the sigmoid colon), thyroid and parathyroid glands, adrenal glands, kidneys, participates in the innervation of the heart and blood vessels (Fig. 251).

Rice. 251. Nervus vagus:

1 - dorsal nucleus of the vagus nerve; 2 - the core of a single path; 3 - the nucleus of the spinal tract of the trigeminal nerve; 4 - double core; 5 - cranial root of the accessory nerve; 6 - vagus nerve; 7 - jugular opening; 8 - upper node of the vagus nerve; 9 - the lower node of the vagus nerve; 10 - pharyngeal branches of the vagus nerve; 11 - connecting branch of the vagus nerve to the sinus branch of the glossopharyngeal nerve; 12 - pharyngeal plexus; 13 - upper laryngeal nerve; 14 - internal branch of the superior laryngeal nerve; 15 - external branch of the superior laryngeal nerve; 16 - the upper cardiac branch of the vagus nerve; 17 - lower cardiac branch of the vagus nerve; 18 - left recurrent laryngeal nerve; 19 - trachea; 20 - cricoid muscle; 21 - lower constrictor of the pharynx; 22 - middle constrictor of the pharynx; 23 - stylo-pharyngeal muscle; 24 - upper constrictor of the pharynx; 25 - palatopharyngeal muscle; 26 - muscle that raises the palatine curtain, 27 - auditory tube; 28 - ear branch of the vagus nerve; 29 - meningeal branch of the vagus nerve; 30 - glossopharyngeal nerve

The vagus nerve contains sensory, motor and autonomic parasympathetic and sympathetic fibers, as well as small ganglions inside the trunk.

Sensory nerve fibers of the vagus nerve originate from afferent pseudo-unipolar nerve cells, clusters of which form 2 sensory node: upper (ganglion superior), located in the jugular foramen, and lower (ganglion inferior), lying at the exit from the hole. The central processes of cells go to the medulla oblongata to the sensitive nucleus - single path core(nucleus tractus solitary), and peripheral - as part of the nerve to the vessels, heart and viscera, where they end with receptor apparatus.

Motor fibers for the muscles of the soft palate, pharynx and larynx originate from the upper cells of the motor double core.

Parasympathetic fibers originate from the autonomic dorsal nucleus (nucleus dorsalis nervi vagi) and spread as part of the nerve to the muscle of the heart, the muscle tissue of the membranes of the vessels and the viscera. Impulses traveling through the parasympathetic fibers reduce the heart rate, dilate blood vessels, constrict the bronchi, and increase the peristalsis of the tubular organs of the gastrointestinal tract.

Autonomous postganglionic sympathetic fibers enter the vagus nerve along its connecting branches with the sympathetic trunk from the cells of the sympathetic nodes and spread along the branches of the vagus nerve to the heart, blood vessels and viscera.

As noted, the glossopharyngeal and accessory nerves are separated from the vagus nerve during development, so the vagus nerve retains connections with these nerves, as well as with the hypoglossal nerve and the sympathetic trunk through connecting branches.

The vagus nerve emerges from the medulla oblongata behind the olive in numerous roots that merge into a common trunk, which leaves the skull through the jugular foramen. Further, the vagus nerve goes down as part of the cervical neurovascular bundle, between the internal jugular vein and the internal carotid artery, and below the level of the upper edge of the thyroid cartilage - between the same vein and the common carotid artery. Through the upper aperture of the chest, the vagus nerve enters the posterior mediastinum between the subclavian vein and artery on the right and anterior to the aortic arch on the left. Here, by branching and connections between the branches, it forms in front of the esophagus (left nerve) and behind it (right nerve) esophageal nerve plexus (plexus oesophagealis), which near the esophageal opening of the diaphragm forms 2 wandering trunk: front

(tractus vagalis anterior) and back (tractus vagalis posterior), corresponding to the left and right vagus nerves. Both trunks leave the chest cavity through the esophagus, give branches to the stomach and end in a number of terminal branches in celiac plexus. From this plexus, the fibers of the vagus nerve spread along its branches. Throughout the vagus nerve, branches depart from it.

Branches of the head of the vagus nerve.

1.Meningeal branch(r. meningeus) starts from the superior node and through the jugular foramen reaches the dura mater of the posterior cranial fossa.

2.ear branch(r. auricularis) goes from the upper node along the anterolateral surface of the bulb of the jugular vein to the entrance to the mastoid canal and further along it to the posterior wall of the external auditory canal and part of the skin of the auricle. On its way, it forms connecting branches with the glossopharyngeal and facial nerves.

Branches of the cervical vagus nerve.

1.Pharyngeal branches(rr. pharyngeales) originate from the lower node or just below it. They take thin branches from the upper cervical node of the sympathetic trunk and between the external and internal carotid arteries penetrate to the lateral wall of the pharynx, on which, together with the pharyngeal branches of the glossopharyngeal nerve and the sympathetic trunk, they form the pharyngeal plexus.

2.superior laryngeal nerve(n. laryngeus superior) branches off from the lower node and goes down and forward along the side wall of the pharynx medially from the internal carotid artery (Fig. 252). At the greater horn, the hyoid bone is divided into two branches: external (r. externus) and internal (r. internus). The external branch connects with the branches from the superior cervical node of the sympathetic trunk and goes along the posterior edge of the thyroid cartilage to the cricoid muscle and the inferior constrictor of the pharynx, and also gives off branches to the arytenoid and lateral cricoarytenoid muscles inconsistently. In addition, branches depart from it to the mucous membrane of the pharynx and the thyroid gland. The internal branch is thicker, sensitive, pierces the thyroid-hyoid membrane and branches in the mucous membrane of the larynx above the glottis, as well as in the mucous membrane of the epiglottis and the anterior wall of the nasal pharynx. Forms a connecting branch with the lower laryngeal nerve.

3.Superior cervical cardiac branches(rr. cardiaci cervicales superiors) - variable in thickness and branch level, usually thin

cues, originate between the superior and recurrent laryngeal nerves and go down to the cervicothoracic nerve plexus.

4. Inferior cervical cardiac branches(rr. cardiaci cervicales inferiors) depart from the laryngeal recurrent nerve and from the trunk of the vagus nerve; participate in the formation of the cervicothoracic nerve plexus.

Branches of the thoracic vagus nerve.

1. recurrent laryngeal nerve(n. laryngeus recurrents) departs from the vagus nerve as it enters the chest cavity. The right recurrent laryngeal nerve bends around the subclavian artery from below and behind, and the left one - the aortic arch. Both nerves rise in the groove between the esophagus and trachea, giving off branches to these organs. terminal branch - inferior laryngeal nerve (n. laryngeus inferior) approaches the throat

Rice. 252. Laryngeal nerves:

a - right side view: 1 - superior laryngeal nerve; 2 - internal branch; 3 - outer branch; 4 - lower constrictor of the pharynx; 5 - crico-pharyngeal part of the lower constrictor of the pharynx; 6 - recurrent laryngeal nerve;

b - the plate of the thyroid cartilage is removed: 1 - the internal branch of the superior laryngeal nerve; 2 - sensitive branches to the mucous membrane of the larynx; 3 - anterior and posterior branches of the lower laryngeal nerve; 4 - recurrent laryngeal nerve

and innervates all the muscles of the larynx, with the exception of the cricoid, and the mucous membrane of the larynx below the vocal cords.

Branches depart from the recurrent laryngeal nerve to the trachea, esophagus, thyroid and parathyroid glands.

2.Thoracic cardiac branches(rr. cardiaci thoracici) start from the vagus and left laryngeal recurrent nerves; participate in the formation of the cervicothoracic plexus.

3.Tracheal branches go to the thoracic trachea.

4.Bronchial branches go to the bronchi.

5.Esophageal branches approach the thoracic esophagus.

6.Pericardial branches innervate the pericardium.

Within the cavities of the neck and chest, the branches of the wandering, recurrent and sympathetic trunks form the cervicothoracic nerve plexus, which includes organ plexuses: thyroid, tracheal, esophageal, pulmonary, cardiac:

Branches of wandering trunks (abdominal part).

1)anterior gastric branches start from the anterior trunk and form the anterior gastric plexus on the anterior surface of the stomach;

2)posterior gastric branches depart from the posterior trunk and form the posterior gastric plexus;

3)celiac branches depart mainly from the posterior trunk and take part in the formation of the celiac plexus;

4)hepatic branches are part of the hepatic plexus;

5)renal branches form renal plexuses.

XI pair - accessory nerve

accessory nerve(n. accessories) mainly motor, separated in the process of development from the vagus nerve. It begins in two parts - vagus and spinal - from the corresponding motor nuclei in the medulla oblongata and spinal cord. Afferent fibers fit into the trunk through the spinal part from the cells of sensory nodes (Fig. 253).

The wandering part comes out cranial root (radix cranialis) from the medulla oblongata below the exit of the vagus nerve, the spinal part is formed spinal root (radix spinalis), emerging from the spinal cord between the posterior and anterior roots.

The spinal part of the nerve rises to the large foramen, enters through it into the cranial cavity, where it connects with the vagus part and forms a common nerve trunk.

In the cranial cavity, the accessory nerve divides into two branches: internal and external.

1. Internal branch(r. internus) approaches the vagus nerve. Through this branch, motor nerve fibers are included in the composition of the vagus nerve, which leave it through the laryngeal nerves. It can be assumed that sensory fibers also pass into the vagus and further into the laryngeal nerve.

Rice. 253. accessory nerve:

1 - double core; 2 - vagus nerve; 3 - cranial root of the accessory nerve; 4 - spinal root of the accessory nerve; 5 - a large hole; 6 - jugular opening; 7 - upper node of the vagus nerve; 8 - accessory nerve; 9 - the lower node of the vagus nerve; 10 - the first spinal nerve;

11 - sternocleidomastoid muscle; 12 - second spinal nerve; 13 - branches of the accessory nerve to the trapezius and sternocleidomastoid muscles; 14 - trapezius muscle

2. outer branch(r. externus) exits the cranial cavity through the jugular foramen to the neck and goes first behind the posterior belly of the digastric muscle, and then from the inside of the sternocleidomastoid muscle. Perforating the last, the external branch goes down and ends in the trapezius muscle. Connections are formed between the accessory and cervical nerves. Innervates the sternocleidomastoid and trapezius muscles.

XII pair - hypoglossal nerve

hypoglossal nerve(n. hypoglossus) predominantly motor, is formed as a result of the fusion of several primary spinal segmental nerves that innervate the hyoid muscles (see Fig. 223).

Nerve fibers that make up the hypoglossal nerve depart from its cells motor nucleus, located in the medulla oblongata (see Fig. 225). The nerve leaves it between the pyramid and the olive with several roots. The formed nerve trunk passes through the hypoglossal nerve canal to the neck, where it is located first between the external (outside) and internal carotid arteries, and then descends under the posterior belly of the digastric muscle in the form of an arc open upwards along the lateral surface of the hyoid muscle, making up the upper side of the Pirogov triangle (lingual triangle) (Fig. 254, see Fig. 193); branches into terminal lingual branches (rr. linguales), innervating muscles of the tongue.

From the middle of the arc of the nerve down along the common carotid artery goes upper root of the cervical loop (radix superior ansae cervicalis), which connects with her lower spine (radix inferior) from the cervical plexus, resulting in the formation cervical loop (ansa cervicalis). Several branches depart from the cervical loop to the muscles of the neck located below the hyoid bone.

The position of the hypoglossal nerve in the neck can be different. In people with a long neck, the arc formed by the nerve lies relatively low, while in people with a short neck it is high. This is important to consider when operating on a nerve.

Other types of fibers also pass through the hypoglossal nerve. Sensitive nerve fibers come from the cells of the inferior node of the vagus nerve and, possibly, from the cells of the spinal nodes along the connecting branches between the hypoglossal, vagus and

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Rice. 254. Hypoglossal nerve:

1 - hypoglossal nerve in the canal of the same name; 2 - the nucleus of the hypoglossal nerve; 3 - the lower node of the vagus nerve; 4 - anterior branches of the 1st-3rd cervical spinal nerves (form a cervical loop); 5 - upper cervical node of the sympathetic trunk; 6 - upper spine of the neck loop; 7 - internal carotid artery; 8 - lower root of the neck loop; 9 - neck loop; 10 - internal jugular vein; 11 - common carotid artery; 12 - lower belly of the scapular-hyoid muscle; 13 - sternothyroid muscle; 14 - sternohyoid muscle; 15 - upper abdomen of the scapular-hyoid muscle; 16 - shield-hyoid muscle; 17 - hyoid-lingual muscle; 18 - chin-hyoid muscle; 19 - chin-lingual muscle; 20 - own muscles of the tongue; 21 - styloid muscle

cervical nerves. Sympathetic fibers enter the hypoglossal nerve along its connecting branch with the superior node of the sympathetic trunk.

Areas of innervation, fiber composition and names of the cranial nerve nuclei are presented in Table. fifteen.

Questions for self-control

1. What nerves depart from the vestibular node?

2. What branches of the glossopharyngeal nerve do you know?

3. What branches depart from the head and cervical parts of the vagus nerve? What do they innervate?

4. What branches of the thoracic and abdominal parts of the vagus nerve do you know? What do they innervate?

5. What do the accessory and hypoglossal nerves innervate?

cervical plexus

cervical plexus (plexus cervicalis) is formed by the anterior branches of the 4 upper cervical spinal nerves (C I -C IV), which have interconnections. The plexus lies on the side of the transverse processes between the vertebral (back) and prevertebral (front) muscles (Fig. 255). The nerves emerge from under the posterior edge of the sternocleidomastoid muscle, slightly above its middle, and fan out upward, forward, and downward. The following nerves depart from the plexus:

1.Lesser occipital nerve(n. occipitalis mino)(from C I -C II) extends upward to the mastoid process and further to the lateral sections of the occiput, where it innervates the skin.

2.Great ear nerve(n. auricularis major)(from C III -C IV) goes along the sternocleidomastoid muscle up and anteriorly, to the auricle, innervates the skin of the auricle (posterior branch) and the skin above the parotid salivary gland (anterior branch).

3.Transverse nerve of the neck(n. transverse colli)(from C III -C IV) goes anteriorly and at the anterior edge of the sternocleidomastoid muscle is divided into upper and lower branches that innervate the skin of the anterior neck.

4.Supraclavicular nerves(nn. supraclavicularis)(From C III -C IV) (numbering 3 to 5) spread downward in a fan-like fashion under the subcutaneous muscle of the neck; branch in the skin of the back of the neck (lateral

Table 15 Areas of innervation, fiber composition and names of cranial nerve nuclei

Continuation of the table. fifteen

The end of the table. fifteen

Rice. 255. cervical plexus:

1 - hypoglossal nerve; 2 - accessory nerve; 3, 14 - sternocleidomastoid muscle; 4 - large ear nerve; 5 - small occipital nerve; 6 - large occipital nerve; nerves to the anterior and lateral rectus muscles of the head; 8 - nerves to the long muscles of the head and neck; 9 - trapezius muscle; 10 - connecting branch to the brachial plexus; 11 - phrenic nerve; 12 - supraclavicular nerves; 13 - lower belly of the scapular-hyoid muscle; 15 - neck loop; 16 - sternohyoid muscle; 17 - sternothyroid muscle; 18 - upper abdomen of the scapular-hyoid muscle; 19 - transverse nerve of the neck; 20 - lower root of the neck loop; 21 - upper spine of the neck loop; 22 - thyroid muscle; 23 - geniohyoid muscle

branches), in the region of the clavicle (intermediate branches) and the upper anterior part of the chest up to the III rib (medial branches).

5. Phrenic nerve(n. phrenicis)(from C III -C IV and partly from C V), predominantly a motor nerve, goes down the anterior scalene muscle into the chest cavity, where it passes to the diaphragm in front of the lung root between the mediastinal pleura and the pericardium. Innervates the diaphragm, gives sensitive branches to the pleura and pericardium (rr. pericardiaci), sometimes to the cervicothoracic neuro-

mu plexus. In addition, it sends diaphragmatic-abdominal branches (rr. phrenicoabdominales) to the peritoneum covering the diaphragm. These branches contain nerve nodes (ganglia phrenici) and connect with the celiac nerve plexus. Especially often, the right phrenic nerve has such connections, which explains the phrenicus symptom - irradiation of pain in the neck with liver disease.

6.Lower spine of the neck loop(radix inferior ansae cervicalis) formed by nerve fibers from the anterior branches of the second and third spinal nerves and goes anteriorly to connect with top spine (radix superior), arising from the hypoglossal nerve (XII pair of cranial nerves). As a result of the connection of both roots, a neck loop is formed. (ansa cervicalis), from which branches depart to the scapular-hyoid, sternohyoid, thyroid-hyoid and sternothyroid muscles.

7.Muscular branches(rr. musculares) go to the prevertebral muscles of the neck, to the muscle that lifts the scapula, as well as to the sternocleidomastoid and trapezius muscles.

Cervical sympathetic trunk lies in front of the transverse processes of the cervical vertebrae on the surface of the deep muscles of the neck (Fig. 256). In each cervical region there are 3 cervical nodes: top, middle (ganglia cervicales superior et media) and cervicothoracic (stellate ) (ganglion cervicothoracicum (stellatum)). The middle cervical node is the smallest. The stellate node often consists of several nodes. The total number of nodes in the cervical region can vary from 2 to 6. Nerves depart from the cervical nodes to the head, neck and chest.

1.gray connecting branches(rr. communicantens grisei)- to the cervical and brachial plexuses.

2.Internal carotid nerve(n. caroticus internus) usually departs from the upper and middle cervical nodes to the internal carotid artery and forms around it internal carotid plexus (plexus caroticus internus), which extends to its branches. Branches from the plexus deep stony nerve (n. petrosus profundus) to the pterygoid node.

3.jugular nerve(n. jugularis) starts from the upper cervical node, within the jugular opening is divided into two branches: one goes to the upper node of the vagus nerve, the other - to the lower node of the glossopharyngeal nerve.

Rice. 256. Cervical department of sympathetic trunk:

1 - glossopharyngeal nerve; 2 - pharyngeal plexus; 3 - pharyngeal branches of the vagus nerve; 4 - external carotid artery and nerve plexus; 5 - upper laryngeal nerve; 6 - internal carotid artery and sinus branch of the glossopharyngeal nerve; 7 - sleepy glomus; 8 - sleepy sinus; 9 - upper cervical cardiac branch of the vagus nerve; 10 - upper cervical cardiac nerve;

11 - middle cervical node of the sympathetic trunk; 12 - middle cervical cardiac nerve; 13 - vertebral node; 14 - recurrent laryngeal nerve; 15 - cervicothoracic (star-shaped) node; 16 - subclavian loop; 17 - vagus nerve; 18 - lower cervical cardiac nerve; 19 - thoracic cardiac sympathetic nerves and branches of the vagus nerve; 20 - subclavian artery; 21 - gray connecting branches; 22 - upper cervical node of the sympathetic trunk; 23 - vagus nerve

4.Vertebral nerve(n. vertebralis) departs from the cervicothoracic node to the vertebral artery, around which it forms vertebral plexus(plexus vertebralis).

5.Cardiac cervical superior, middle and inferior nerves(nn. cardiaci cervicales superior, medius et inferior) originate from the corresponding cervical nodes and are part of the cervicothoracic nerve plexus.

6.External carotid nerves(nn. carotici externi) depart from the upper and middle cervical nodes to the external carotid artery, where they participate in the formation external carotid plexus (plexus caroticus externus), which extends to the branches of the artery.

7.Laryngo-pharyngeal branches(rr. laryngopharyngei) go from the superior cervical ganglion to the pharyngeal plexus and as a connecting branch to the superior laryngeal nerve.

8.Subclavian branches(rr. subclavii) move away from subclavian loop (ansa subclavia), which is formed by the division of the internodal branch between the middle cervical and cervicothoracic nodes.

Cranial division of the parasympathetic nervous system

Centers cranial department The parasympathetic part of the autonomic nervous system is represented by nuclei in the brainstem (mesencephalic and bulbar nuclei).

Mesencephalic parasympathetic nucleus - accessory nucleus of the oculomotor nerve (nucleus accessories n. oculomotorii)- located at the bottom of the aqueduct of the midbrain, medial to the motor nucleus of the oculomotor nerve. Preganglionic parasympathetic fibers run from this nucleus as part of the oculomotor nerve to the ciliary ganglion.

The following parasympathetic nuclei lie in the medulla oblongata and pons:

1)superior salivary nucleus(nucleus salivatorius superior), associated with the facial nerve - in the bridge;

2)inferior salivary nucleus(nucleus salivatorius inferior), associated with the glossopharyngeal nerve - in the medulla oblongata;

3)dorsal nucleus of the vagus nerve(nucleus dorsalis nervi vagi),- in the medulla oblongata.

Preganglionic parasympathetic fibers pass from the cells of the salivary nuclei as part of the facial and glossopharyngeal nerves to the submandibular, sublingual, pterygopalatine and ear nodes.

Peripheral department parasympathetic nervous system is formed by preganglionic nerve fibers, occurring

from the indicated cranial nuclei (they pass as part of the corresponding nerves: III, VII, IX, X pairs), the nodes listed above and their branches containing postganglionic nerve fibers.

1. Preganglionic nerve fibers, which are part of the oculomotor nerve, follow to the ciliary node and end on its cells with synapses. Depart from the node short ciliary nerves (nn. ciliares breves), in which, along with sensory fibers, there are parasympathetic: they innervate the sphincter of the pupil and the ciliary muscle.

2. Preganglionic fibers from the cells of the superior salivary nucleus spread as part of the intermediate nerve, from it through the large stony nerve they go to the pterygopalatine node, and through the tympanic string to the submandibular and hyoid nodes, where they end in synapses. Postganglionic fibers follow from these nodes along their branches to the working organs (submandibular and sublingual salivary glands, glands of the palate, nose and tongue).

3. Preganglionic fibers from the cells of the lower salivary nucleus go as part of the glossopharyngeal nerve and further along the small stony nerve to the ear node, on the cells of which they end in synapses. Postganglionic fibers from the cells of the ear node exit as part of the ear-temporal nerve and innervate the parotid gland.

Preganglionic parasympathetic fibers, starting from the cells of the dorsal node of the vagus nerve, pass as part of the vagus nerve, which is the main conductor of parasympathetic fibers. Switching to postganglionic fibers occurs mainly in the small ganglia of the intramural nerve plexuses of most internal organs, so postganglionic parasympathetic fibers appear to be very short compared to preganglionic ones.

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In mammals, including humans, there are 12 pairs of cranial (cranial) nerves, in fish and amphibians - 10, since they have XI and XII pairs of nerves extending from the spinal cord.

The cranial nerves contain afferent (sensory) and efferent (motor) fibers of the peripheral nervous system. Sensitive nerve fibers begin with terminal receptor endings that perceive changes that occur in the external or internal environment of the body. These receptor endings can enter the sense organs (organs of hearing, balance, vision, taste, smell), or, like skin receptors, form encapsulated and non-encapsulated endings that are sensitive to tactile, temperature, and other stimuli. Sensory fibers carry impulses to the CNS. Like the spinal nerves, in the cranial nerves sensory neurons lie outside the CNS in the ganglia. The dendrites of these neurons go to the periphery, and the axons follow to the brain, mainly to the brainstem, and reach the corresponding nuclei.

Motor fibers innervate skeletal muscles. They form neuromuscular synapses on muscle fibers. Depending on which fibers predominate in the nerve, it is called sensitive (sensory) or motor (motor). If a nerve contains both types of fibers, it is called a mixed nerve. In addition to these two types of fibers, some cranial nerves contain fibers of the autonomic nervous system, its parasympathetic division.

I pair - olfactory nerves and II pair - optic nerve

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I couple- olfactory nerves (n. olfactorii) and II couple- the optic nerve (p. opticus) occupy a special position: they are referred to the conductive department of the analyzers and are described together with the corresponding sense organs. They develop as outgrowths of the anterior bladder of the brain and are pathways (tracts) rather than typical nerves.

III–XII pairs of cranial nerves

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III-XII cranial nerves differ from the spinal nerves due to the fact that the conditions for the development of the head and brain are different than the conditions for the development of the trunk and spinal cord. Due to the reduction of myotomes, few neurotomes remain in the head region. At the same time, the cranial nerves innervating the myotomes are homologous to the incomplete spinal nerve, which is composed of the ventral (motor) and dorsal (sensitive) roots. Each somatic cranial nerve contains fibers that are homologous to one of these two roots. In view of the fact that derivatives of the gill apparatus take part in the formation of the head, the composition of the cranial nerves also includes fibers that innervate formations that develop from the muscles of the visceral arches.

III, IV, VI and XII pairs of cranial nerves

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III, IV, VI and XII pairs of cranial nerves - oculomotor, trochlear, abducent and hypoglossal - are motor and correspond to the ventral, or anterior, roots of the spinal nerves. However, in addition to motor fibers, they also contain afferent fibers, along which proprioceptive impulses rise from the musculoskeletal system. III, IV and VI nerves branch in the muscles of the eyeball, originating from the three anterior (anterior) myotomes, and XII in the muscles of the tongue, developing from the occipital myotomes.

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VIII pair - the vestibulocochlear nerve consists only of sensory fibers and corresponds to the dorsal root of the spinal nerves.

V, VII, IX and X pairs of cranial nerves

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V, VII, IX and X pairs - trigeminal, facial, glossopharyngeal and vagus nerves contain sensory fibers and are homologous to the dorsal roots of the spinal nerves. Like the latter, they consist of neurite cells of the sensory ganglia of the corresponding nerve. These cranial nerves also contain motor fibers related to the visceral apparatus. The fibers passing as part of the trigeminal nerve innervate the muscles that originated from the muscles of the 1st visceral, jaw arch; as part of the facial - derivatives of the muscles of the II visceral, hyoid arch; in the composition of the glossopharyngeal - derivatives of the I gill arch, and the vagus nerve - derivatives of the mesoderm II and all subsequent gill arches.

XI pair - accessory nerve

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XI pair - the accessory nerve consists only of the motor fibers of the gill apparatus and acquires the significance of a cranial nerve only in higher vertebrates. The accessory nerve innervates the trapezius muscle, which develops from the musculature of the last branchial arches, and the sternocleidomastoid muscle, which in mammals is isolated from the trapezius.

III, VII, IX, X pairs of cranial nerves

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III, VII, IX, X cranial nerves also contain unmyelinated parasympathetic fibers of the autonomic nervous system. In the III, VII and IX nerves, these fibers innervate the smooth muscles of the eye and glands of the head: salivary, lacrimal and mucous. The X nerve carries parasympathetic fibers to the glands and smooth muscles of the internal organs of the neck, thoracic and abdominal cavities. Such a length of the area of ​​branching of the vagus nerve (hence its name) is explained by the fact that the organs innervated by it at the early stages of phylogenesis lay near the head and in the region of the gill apparatus, and then gradually moved back during evolution, pulling the nerve fibers behind them.

Branching of the cranial nerves. All cranial nerves, with the exception of IV, depart from the base of the brain ().

III pair - oculomotor nerve

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III pair - the oculomotor nerve (p. oculomotorius) is formed by neurites of the cells of the nucleus of the oculomotor nerve, which lies in front of the central gray matter of the water supply (see Atl.). In addition, this nerve has an accessory (parasympathetic) nucleus. The nerve is mixed, it emerges on the surface of the brain near the anterior edge of the bridge between the legs of the brain and penetrates the orbit through the upper orbital fissure. Here, the oculomotor nerve innervates almost all the muscles of the eyeball and upper eyelid (see Atl.). Parasympathetic fibers after the nerve enters the orbit leave it and go to the ciliary node. The nerve also contains sympathetic fibers from the internal carotid plexus.

IV pair - trochlear nerve

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IV pair - trochlear nerve (n. trochlearis) consists of fibers of the nucleus of the trochlear nerve, located in front of the water supply. The axons of the neurons of this nucleus move to the opposite side, form a nerve and exit to the surface of the brain from the anterior cerebral sail (). The nerve goes around the leg of the brain and through the upper orbital fissure enters the orbit, where it innervates the superior oblique muscle of the eye (see Atl.).

V pair - trigeminal nerve

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V pair - the trigeminal nerve (n. trigeminus) appears on the surface of the brain between the bridge and the middle legs of the cerebellum with two roots: large - sensitive and small - motor (see Atl.).

The sensory root consists of neurites of the sensory neurons of the trigeminal ganglion, which is located on the anterior surface of the temporal bone pyramid, near its apex. Entering the brain, these fibers terminate in three switching nuclei located: in the tegmentum of the bridge, along the medulla oblongata and cervical spinal cord, on the sides of the aqueduct. The dendrites of the cells of the trigeminal node form three main branches of the trigeminal nerve (hence its name): the ophthalmic, maxillary and mandibular nerves, which innervate the skin of the forehead and face, teeth, the mucous membrane of the tongue, oral cavities and nose (see Atl.; Fig. 3.28 ). Thus, the sensory root of the V pair of nerves corresponds to the dorsal sensory root of the spinal nerve.

Rice. 3.28. Trigeminal nerve (sensory root):
1 - mesencephalic nucleus; 2 - the main sensory nucleus; 3 - IV ventricle; 4 - spinal nucleus; 5 - mandibular nerve; 6 - maxillary nerve; 7 - ophthalmic nerve; 8 - sensory root; 9 - trigeminal ganglion

The motor root contains processes of cells of the motor nucleus, which lies in the tegmentum of the bridge, medial to the switching upper sensory nucleus. Having reached the trigeminal node, the motor root bypasses it, enters the mandibular nerve, exits the skull through the foramen ovale and supplies all the masticatory and other muscles developing from the jaw arch with its fibers. Thus, the motor fibers of this root are of visceral origin.

VI pair - abducens nerve

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VI pair - abducens nerve (p. abducens), consists of fibers of cells of the nucleus of the same name, lying in the rhomboid fossa. The nerve emerges on the surface of the brain between the pyramid and the bridge, penetrates through the upper orbital fissure into the orbit, where it innervates the external rectus muscle of the eye (see Atl.).

VII pair - facial nerve

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VII pair - facial nerve (p. facialis), consists of fibers of the motor nucleus, which lies in the tire of the bridge. Together with the facial nerve, the intermediate nerve is considered, the fibers of which join it. Both nerves emerge on the surface of the brain between the pons and the medulla oblongata, lateral to the abducens nerve. Through the internal auditory opening, the facial nerve, together with the intermediate one, enters the canal of the facial nerve, penetrating the pyramid of the temporal bone. In the canal of the facial nerve lies geniculate ganglion - sensory ganglion of the intermediate nerve. It gets its name from the kink (knee) that forms the nerve in the bend of the canal. Having passed the canal, the facial nerve separates from the intermediate one, exits through the stylomastoid opening into the thickness of the parotid salivary gland, where it splits into terminal branches that form the "great crow's foot" (see Atl.). These branches innervate all facial muscles, the subcutaneous muscle of the neck and other muscles derived from the mesoderm of the hyoid arch. The nerve thus belongs to the visceral apparatus.

Intermediate nerve consists of a small number of fibers that extend from geniculate ganglion, lying in the initial part of the facial canal. Entering the brain, these fibers terminate in the pontine operculum (on the cells of the nucleus of a single bundle). The dendrites of the cranked ganglion cells go as part of the tympanic string - a branch of the intermediate nerve, and then join the lingual nerve (a branch of the V pair) and innervate the taste (mushroom and foliate) papillae of the tongue. These fibers, carrying impulses from the organs of taste, are homologous to the dorsal roots of the spinal cord. The remaining fibers of the intermediate nerve are parasympathetic, they originate from the superior salivary nucleus. These fibers reach the pterygopalatine node.

VIII pair - vestibulocochlear nerve

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VIII pair - vestibulocochlear nerve (p. vestibulocochlearis), consists of sensory fibers of the cochlear nerve and vestibule nerve.

cochlear nerve conducts impulses from the organ of hearing and is represented by cell neurites spiral knot, lying inside the bony cochlea.

Nerve of vestibule carries impulses from the vestibular apparatus; they signal the position of the head and body in space. The nerve is represented by neurites of cells vestibular node, located at the bottom of the internal auditory canal.

The neurites of the vestibular nerve and the cochlear nerve join in the internal auditory canal to form the common vestibulocochlear nerve, which enters the brain near the intermediate and facial nerves lateral to the olive of the medulla oblongata.

The nerve fibers of the cochlea terminate in the dorsal and ventral auditory nuclei of the pontine tegmentum, the nerve fibers of the vestibule terminate in the vestibular nuclei of the rhomboid fossa (see Atl.).

IX pair - glossopharyngeal nerve

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IX pair - glossopharyngeal nerve (p. glossopharyngeus), appears on the surface of the medulla oblongata, outside of the olive, with several roots (from 4 to 6); exits the cranial cavity as a common trunk through the jugular foramen. The nerve consists mainly of sensory fibers that innervate the trough papillae and the mucous membrane of the posterior third of the tongue, the mucous membrane of the pharynx and middle ear (see Atl.). These fibers are the dendrites of the cells of the sensory nodes of the glossopharyngeal nerve located in the area of ​​the jugular foramen. The neurites of the cells of these nodes terminate in the switching nucleus (single bundle), under the bottom of the fourth ventricle. Part of the fibers passes to the posterior nucleus of the vagus nerve. The described part of the glossopharyngeal nerve is homologous to the dorsal roots of the spinal nerves.

The nerve is mixed. It also contains motor fibers of gill origin. They start from the motor (double) nucleus of the tegmentum oblongata and innervate the muscles of the pharynx. These fibers represent nerve I of the gill arch.

The parasympathetic fibers that make up the nerve originate from the lower salivary nucleus.

X pair - vagus nerve

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X pair - vagus nerve (p. vagus), the longest of the cranial, exits the medulla oblongata behind the glossopharyngeal with several roots and leaves the skull through the jugular foramen along with IX and XI pairs. Near the opening are the ganglia of the vagus nerve, giving rise to its sensitive fibers(see Atl.). Having descended along the neck as part of its neurovascular bundle, the nerve is located in the chest cavity along the esophagus (see Atl.), and the left one gradually shifts to the anterior, and the right to its posterior surface, which is associated with the rotation of the stomach in embryogenesis. Having passed along with the esophagus through the diaphragm into the abdominal cavity, the left nerve branches on the anterior surface of the stomach, and the right one is part of celiac plexus.

Sensitive fibers of the vagus nerve innervate the mucous membrane of the pharynx, larynx, root of the tongue, as well as the hard shell of the brain and are the dendrites of the cells of its sensitive ganglia. Cell dendrites terminate in the nucleus of a single bundle. This nucleus, like the double nucleus, is common to the nerves of the IX and X pairs.

motor fibers vagus nerve depart from the cells of the double nucleus of the tegmentum oblongata. The fibers belong to the nerve of the II branchial arch; they innervate derivatives of its mesoderm: the muscles of the larynx, palatine arches, soft palate and pharynx.

The bulk of the fibers of the vagus nerve are parasympathetic fibers, originating from the cells of the posterior nucleus of the vagus nerve and innervating the insides.

XI pair - accessory nerve

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XI pair - accessory nerve (p. accessorius), consists of fibers of the cells of the double nucleus (common with the IX and X nerves), which lies in the medulla oblongata outside the central canal, and the fibers of its spinal nucleus, which is located in the anterior horns of the spinal cord for 5–6 cervical segments. The roots of the spinal nucleus, having folded into a common trunk, enter the skull through the foramen magnum, where they join the roots of the cranial nucleus. The latter, in the amount of 3–6, come out behind the olive, located directly behind the roots of the X pair.

The accessory nerve exits the skull along with the glossopharyngeal and vagus nerves through the jugular foramen. Here are the fibers inner branch pass into the vagus nerve (see Atl.).

enters the cervical plexus and innervates the trapezius and sternocleidomastoid muscles - derivatives of the gill apparatus (see Atl.).

The cranial nerves make our lives easier every day, as they provide the functioning of our body and the connection of the brain with the senses.

What it is?

How many of them are there and what functions does each of them perform? How are they classified?

General information

The cranial nerve is a collection of nerves that begin or end in the brain stem. There are 12 nerve pairs in total. Their numbering is based on the order of release:

• I - responsible for the sense of smell
• II - responsible for vision
• III - allows the eyes to move
• IV - directs the eyeball down and outward;
• V - is responsible for the measure of sensitivity of facial tissues.
• VI - abducts the eyeball
• VII - connects the facial muscles and lacrimal glands with the central nervous system (central nervous system);
• VIII - transmits auditory impulses, as well as impulses emitted by the vestibular part of the inner ear;
• IX - sets in motion the stylo-pharyngeal muscle, which lifts the pharynx, connects the parotid gland with the central nervous system, makes the tonsils, pharynx, soft palate, etc. sensitive;
• X - innervates the chest and abdominal cavities, cervical organs and organs of the head;
• XI - provides nerve cells to muscle tissues that turn the head and raise the shoulder;
• XII - responsible for the movements of the tongue muscles.

Leaving the area of ​​the brain, the cranial nerves go to the skull, which has characteristic openings under them. Through them they go out, and then there is a branching.

Each of the nerves of the skull is different both in composition and functionality.

How does it differ from, for example, the nerve of the spinal cord: the nerves of the spinal cord are predominantly mixed, and diverge only in the peripheral region, where they are divided into 2 types. FMN are either one or the other type and in most cases are not mixed. Pairs I, II, VIII are sensory, and III, IV, VI, XI, XII are motor. The rest are mixed.

Classification

There are 2 fundamental classifications of nerve pairs: by location and functionality:
Exit location:

• emerging above the brain stem: I, II;
• the exit point is the midbrain: III, IV;
• the exit point is the Varoliev Bridge: VIII, VII, VI, V;
• the exit point is the medulla oblongata, or rather its bulb: IX,X,XII and XI.

By functional purpose:

• perception functions: I, II, VI, VIII;
• motor activity of the eyes and eyelids: III, IV, VI;
• motor activity of the cervical and tongue muscles: XI and XII
• parasympathetic functions: III, VII, IX, X

Let's take a closer look at the functionality:

ChMN functionality

sensitive group

I - olfactory nerve.
It consists of receptors, which are thin processes, thickening towards the end. On the ends of the processes there are special hairs that capture odors.
II - the nerve of vision.
It runs through the entire eye, ending in the canal of vision. At the exit from it, the nerves cross, after which they continue their movement to the central part of the brain. The nerve of vision delivers signals received from the outside world to the desired compartments of the brain.
VIII - vestibulocochlear nerve.
Belongs to the sensory type. Consists of 2 components, different in their functionality. The first conducts impulses coming from the vestibule of the inner ear, and the second transmits hearing impulses that come from the cochlea. In addition, the vestibular component is involved in regulating the position of the body, arms, legs and head and, in general, coordinates movements.

motor group

III - oculomotor nerve.

These are processes of nuclei. Runs from the midbrain to the orbit. Its function is to engage the muscles of the eyelash, which carry out accommodation, and the muscle that constricts the pupil.

IV - trochlear nerve.

Refers to the motor type, is located in the orbit, getting there through the gap from above (on the side of the previous nerve). It ends at the eyeball, or rather its upper muscle, which it provides with nerve cells.

VI - abducens nerve.

Like the block one, it is motorized. It is formed by shoots. It is located in the eye, where it penetrates from above, and provides nerve cells to the outer muscle of the eye.

XI - accessory nerve.

Representative of the motor type. dual core. The nuclei are located in the spinal cord and medulla oblongata.

XII - hypoglossal nerve.

Type - motor. Nucleus in the medulla oblongata. Provides nerve cells to the muscles and muscles of the tongue and some parts of the neck.

mixed group

V - trigeminal.

thickness leader. It got its name because it has several branches: ophthalmic, lower and maxillary.

VII - facial nerve.

It has a front and an intermediate component. The facial nerve forms 3 branches and provides normal movement of the muscles of the face.

IX - glossopharyngeal nerve.

Belongs to the mixed type. Consists of three types of fibers.

X - vagus nerve.

Another representative of the mixed type. Its length exceeds the length of the others. Consists of three types of fibers. One branch is the depressor nerve, ending in the aortic arch, which regulates blood pressure. The remaining branches, which have a higher susceptibility, provide nerve cells for the brain membrane and the skin of the ears.

It can be divided (conditionally) into 4 parts: the head section, the neck section, the chest section and the abdominal section. Branches extending from the head are sent to the brain and are called meningeal. And those that go to the ears - ear. The pharyngeal branches come from the neck, and the cardiac branches and thoracic branches, respectively, depart from the chest. Branches directed to the plexus of the esophagus are called esophageal.

What can defeat lead to?

Symptoms of lesions depend on which nerve was damaged:

Olfactory nerve

Symptoms are more or less pronounced, depending on the strength of the nerve lesion. Basically, the lesion is manifested in the fact that a person either smells more sharply, or does not distinguish between them, or does not feel at all. In a special place, you can put cases when symptoms appear only on one side, since their bilateral manifestation usually means that a person has chronic rhinitis

optic nerve

If it is struck, vision deteriorates up to blindness on the side where it happened. If part of the retinal neurons is affected or when a scotoma is formed, there is a risk of local loss of vision in a certain area of ​​the eye. If blindness develops bilaterally, this means that the optic fibers were affected at the crosshairs. If there is damage to the middle visual fibers, which completely intersect, then half of the visual field may fall out.

However, there are also cases when the visual field falls out in only one eye. This is usually due to damage to the optic tract itself.

oculomotor nerve

When the nerve trunk is affected, the eyes stop moving. If only part of the nucleus is affected, then the external muscle of the eye becomes immobilized or very weak. If, nevertheless, complete paralysis has come, then the patient has no way to open his eyes (eyes). If the muscle responsible for lifting the eyelid is very weak, but still functioning, the patient will be able to open the eye, but only partially. The muscle that lifts the eyelid is usually the last to be damaged. But if the damage has reached it, then this can cause divergent strabismus or external ophthalmoplegia.

Block nerve

The defeat of this pair is quite rare. It is expressed in the fact that the eyeball loses the ability to move freely outward and down. This happens due to a violation of innervation. The eyeball seems to freeze in a position turned inward and upward. A characteristic feature of such damage will be bifurcation or diplopia, when the patient tries to look down, to the right, or to the left.

Trigeminal nerve

The main symptom is a segmental disturbance of perception. Sometimes sensitivity to pain or temperature can be completely lost. At the same time, the feeling of a change in pressure or other deeper changes are perceived adequately.

If the facial nerve is inflamed, then that half of the face that was affected hurts. The pain is localized in the ear region. Sometimes the pain can move to the lips, forehead or lower jaw. If the optic nerve is affected, then the corneal and superciliary reflexes disappear.

In cases of damage to the mandibular nerve, the tongue almost completely (on 2/3 of its area) loses the ability to distinguish tastes, and if its motor fiber is damaged, it can paralyze the masticatory muscles.

Abducens nerve

The main symptom is convergent strabismus. Most often, patients complain that they see double in their eyes, and those objects that are located horizontally double.

However, the defeat of this particular pair separately from others is rare. Most often, 3 pairs of nerves (III, IV and VI) are affected at once, due to the proximity of their fibers. But if the lesion has already occurred at the exit of the skull, then most likely the lesion will reach the nominal abducens nerve, in view of its greater length in comparison with the others.

facial nerve

If the motor fibers are damaged, it can paralyze the face. Facial paralysis occurs on the affected half, which is manifested in facial asymmetry. This is complemented by Bell's syndrome - when you try to close the affected half - the eyeball turns up.

Since one half of the face is paralyzed, the eye does not blink and begins to water - this is called paralytic lacrimation. Mimic muscles can also be immobilized if the motor nucleus of the nerve is damaged. If the lesion has also affected the radicular fibers, then this is fraught with the manifestation of the Miyar-Gubler syndrome, which manifests itself in blocking the movement of the arms and legs in the unaffected half.

Vestibulocochlear nerve

With damage to the nerve fibers, hearing is not lost at all.
However, various auditory, irritation and hearing loss, up to deafness, can easily manifest themselves when the nerve itself is damaged. Hearing acuity is reduced if the lesion is receptor in nature or if the anterior or posterior nucleus of the cochlear component of the nerve is damaged.

Glossopharyngeal nerve

If he is struck by the back of the tongue, he ceases to distinguish tastes, the top of the throat loses its susceptibility, the person confuses tastes. Loss of taste is most likely with damage to the projection cortical areas. If the nerve is irritated directly, then the patient feels a burning pain of ragged intensity in the tonsils and tongue, at intervals of 1-2 minutes. Pain can also radiate to the ear and throat. On palpation, more often between attacks, the pain sensation is most severe behind the lower jaw.

Nervus vagus

If it is affected, the esophageal and swallowing muscles are paralyzed. It becomes impossible to swallow, and liquid food enters the nasal cavity. The patient speaks through the nose, wheezing, as the vocal cords are also paralyzed. If the nerve is affected on both sides, then a suffocating effect may occur. Bari- and tachycardia begins, breathing is disturbed and a malfunction of the heart may occur.

accessory nerve

If the lesion is one-sided, then it becomes difficult for the patient to raise his shoulders, his head does not turn in the direction that is opposite to the affected area. But in the direction of the affected area, she leans willingly. If the lesion is bilateral, then the head cannot turn in either direction, and is thrown back.

hypoglossal nerve

If it is affected, then the tongue will be completely or partially paralyzed. Paralysis of the periphery of the tongue is most likely if the nucleus or nerve fibers are affected. If the lesion is unilateral, the functionality of the tongue is slightly reduced, but if it is bilateral, the tongue paralyzes, and at the same time it can paralyze the limbs.