Anatomy of the facial nerve its path from the skull to the face branches. Facial nerve: anatomy, scheme, structure, functions and features. VII pair - facial nerves

The facial nerve is the seventh pair of twelve cranial nerves, which includes motor, secretory and proprioceptive fibers; he is responsible for the work of the facial muscles of the tongue, innervates the glands of external secretion and is responsible for the sensation of taste in the anterior 2/3 of the tongue.

Location and zones of innervation

The topographic anatomy of the facial nerve is quite confusing. This is due to its complex anatomy and the fact that in its length it goes through the facial canal of the temporal bone, gives and receives processes (branches).

The facial nerve begins not from one, but simultaneously from three nuclei: the nucleus motorius nervi facialis (motor fibers), the nucleus solitaries (sensory fibers) and the nucleus salivatorius superior (secretory fibers). Further, the facial nerve penetrates through the auditory opening into the thickness of the temporal bone directly into the internal auditory meatus. At this stage, fibers of the intermediate nerve are attached.

With various head injuries in the facial canal of the temporal bone, a pinched nerve occurs. Also in this anatomical formation is a thickening called the geniculate ganglion.

Then the facial nerve exits to the base of the skull through an opening near the stylomastoid process, where such branches are separated from it: the posterior auricular nerve, stylohyoid, lingual and digastric branches. They are called so because they innervate the corresponding muscles or organs.

After the facial nerve leaves the canal, it passes through the parotid salivary gland, where it divides into its main branches.

Each branch sends nerve signals to its own "section" of the head and neck.

Branches that arise in front of the parotid salivary gland

Diseases

According to ICD 10, the most common diseases of the facial nerve are neuropathy and neuritis. According to the localization of damage, peripheral and central lesions of the facial nerve are distinguished.

Neuritis or paresis is a pathological condition of an inflammatory nature, and neuropathy of the facial nerve has a different etiology.

The most common cause of these diseases is hypothermia. Everyone knows that if the nerve is stiff, then it starts to hurt, and the facial muscles become naughty. Also, etiological factors include infections (poliomyelitis, herpes virus, measles), craniocerebral trauma and pinching of certain parts of the nerve (especially at the exit of the nerve), vascular disorders of the brain (ischemic and hemorrhagic stroke, atherosclerotic changes), inflammatory diseases of nearby areas of the head and neck.

Damage to the facial nerve is primarily accompanied by paresis or paralysis of the facial muscles. These symptoms are due to the large predominance of motor fibers.

If the facial nerve is damaged in the peripheral parts, then the patient has a pronounced asymmetry of the face. It is more pronounced with various facial movements. The patient has a lowered corner of the mouth, on the damaged side the skin in the forehead is not folded. The symptom of "sailing" of the cheek and the symptom of Bell are pathognomonic.

In addition to motor disorders, patients complain of intense pain, which occurs first in the area of ​​the mastoid process, and then “moves” along the course of the facial nerve and its branches.

Of the autonomic disorders, a decrease or pathological increase in the discharge of the lacrimal gland, a transient hearing disorder, taste disturbances in the region of the innervation of the lingual branch, and a violation of salivation are noted.

Most often, the defeat of the facial nerve is unilateral and in such cases the asymmetry is very noticeable.

With the central localization of damage, the facial muscles stop working on the side that is opposite to the pathological focus. The musculature of the lower part of the face is most often affected.

Therapy Methods

Treatment of various diseases of the facial nerve includes medical, surgical, and sometimes folk methods. The fastest results are obtained by a combination of all these areas of treatment.

If you seek medical help in the initial stages of the disease, then the chances of a full recovery without relapse are quite high. In the case when the patient tries to treat himself without any effect, in most cases the disease becomes chronic.

It is also important to establish the etiological factor for the choice of treatment tactics and the expected prognosis. If, for example, neuritis of the facial nerve is caused by the herpes simplex virus, then etiotropic therapy will be zovirax, acyclovir. When pinched as a result of a traumatic brain injury, first of all, surgical treatment should be resorted to.

Conservative therapy

Medical treatment is more symptomatic than radical.

In order to relieve inflammation, it is necessary to prescribe non-steroidal anti-inflammatory drugs (diclofenac, meloxicam, nimesulide) or hormonal glucocorticosteroids (prednisolone, dexamethasone).

To reduce edema and, as a result, reduce pressure on the nerve, diuretics (furosemide, spironolactone) are used. With prolonged use of non-potassium-sparing diuretics, potassium preparations should be prescribed to maintain electrolyte balance.

To improve blood circulation and nutrition of the damaged area, neuropathologists prescribe vasodilators. For the same purpose, various warming ointments are used.

To restore the structure of the nerve fiber after it is pinched, you can use preparations of B vitamins and metabolic agents.

Physiotherapy is a general therapeutic method of treatment. Her various methods are prescribed within a week after the start of medication. UHF of weak thermal intensity is used as a source of dry heat. To improve the local penetration of drugs, electrophoresis with dibazol, B vitamins, prozerin is used. The electrodes can be placed directly on the skin or in the nasal passages (intranasal).

The facial nerve is a rather complex anatomical formation and its full recovery can take a long time.

Surgical methods

Surgical treatment is indicated when conservative therapy does not bring the expected results. Most often, it is resorted to in cases where there is a complete or partial rupture of the nerve fiber. But good results from surgery can be expected for those patients who seek help during the first year.

In many cases, autotransplantation of the facial nerve is performed, that is, the doctor takes a part from a large nerve trunk and replaces the damaged tissue with it. Most often this is the femoral nerve, since its anatomy and topography are convenient for this procedure.

Also, surgical treatment is resorted to if conservative therapy has not yielded results within ten months.

In case of pinching due to the progression of the oncological process, maxillofacial surgeons first of all remove the tumor or enlarged lymph nodes.

Folk ways

Various inflammatory processes, including pinching of the facial nerve, can also be treated with traditional medicine. Not desirable
use only this type of treatment, but alternative methods work very well as additional means.

To restore muscle function and improve the conduction of nerve impulses, you can do acupressure Chinese massage. Stroking movements should be made in three directions - from the zygomatic bone to the nose, upper jaw and eyeball.

It should be remembered that neuropathy of the facial nerve is well treated with dry heat. For this purpose, it is recommended to tie a knitted woolen scarf around at night or attach a bag to the affected area in salt or fine sand heated in a pan.

Be sure to do therapeutic exercises several times a day - raise your eyebrows, puff out your cheeks, frown, smile, stretch your lips into a tube.

Chamomile infusion can be applied in the form of compresses. Chamomile is anti-inflammatory and reduces pain. For the same purpose, fresh juice of horseradish or radish is used.

Intracranial - from the brain stem to the internal auditory canal;

Canal - internal auditory canal;

Labyrinth - from the opening of the internal auditory canal to the ganglion geniculi - the first knee - gives n.petrosus major - the parasympathetic branch to the lacrimal glands;

Drum - from the first kalena to the pyramidal ledge (second knee);

Mastoid - from the pyramidal protrusion to the stylomastoid opening - departs n.stapedius, to the stirrup muscle, and chorda tympani, secretory innervation of the submandibular and sublingual salivary glands, taste innervation for the anterior 2/3 of the tongue;

Extratemporal - from the stylomastoid opening to the facial muscles.

2. Anatomical and physiological features of the facial nerve

facial nerve ( n. facialis) (VII pair of cranial nerves) develops in connection with the formation of the second gill arch and innervates all the facial muscles and partly the muscles of the floor of the mouth. The nerve is mixed, includes motor fibers from the efferent brain nucleus, as well as sensory and autonomic (gustatory and secretory) fibers belonging to the intermediary nerve, which is closely connected with the facial ( n. intermediate), which runs partially together with the front, being, as it were, its back root (Fig. 1). Rice. one. Anatomical and topographic diagram of the structure of the facial nerve: 1 - the bottom of the IV ventricle, 2 - the nucleus of the facial nerve, 3 - the stylomastoid opening, 4 - the posterior auricular muscle, 5 - the occipital vein, 6 - the posterior belly of the digastric muscle, 7 - the stylohyoid muscle, 8 - branches of the facial nerve to the mimic muscles and subcutaneous muscle of the neck, 9 - the muscle that lowers the angle of the mouth, 10 - the chin muscle, 11 - the muscle that lowers the lower lip, 12 - the cheek muscle, 13 - the circular muscle of the mouth, 14, 15 - the muscle that raises upper lip, 16 - zygomatic muscle, 17 - circular muscle of the eye, 18 - muscle wrinkling the eyebrow, 19 - frontal muscle, 20 - drum string, 21 - lingual nerve, 22 - pterygopalatine node, 23 - trigeminal node, 24 - internal carotid artery, 25 - intermediate nerve, 26 - facial nerve, 27 - vestibulocochlear nerve [V.A. Karlov, 1991]

The motor nucleus of the facial nerve, consisting of large motor cells, is located at the bottom of the IV ventricle, in the reticular formation of the back of the brain. Nerve fibers from this nucleus form the intracerebral section of the facial nerve root, which has a complex topography in the thickness of the pons (Fig. 2).

Rice. 2. The location of the nuclei of the facial nerve and the course of its root in the brain stem (according to Braus): 1 - red nucleus, 2 - Sylvian aqueduct (midbrain cavity), 3 - plate of the quadrigemina, 4 - epiphysis, 5 - middle cerebral path of the trigeminal nerve, 6 - block nerve, 7 - frenulum of the anterior cerebral sail, 8 - motor nucleus of the trigeminal nerve, 9 - knee of the facial nerve (loop n. facialis covering the nucleus of the abducens nerve), 10 - roof of the IV ventricle or tent, 11 - plexus of the meninges of the IV ventricle, 12 - single path, 13 - nucleus of the gray wing (nucleus of the vagus nerve), 14 - nucleus of the hypoglossal nerve, 15 - central canal, 16 - spinal tract of the trigeminal nerve, 17 - accessory nerve, 18 - core of the accessory nerve, 19 - hypoglossal nerve, 20 - accessory nerve, 21 - vagus nerve, 22 - double nucleus, 23 - hypoglossal nerve, 24 - glossopharyngeal nerve, 25 - lower nucleus of the olive, 26 - salivary nucleus, 27 - acoustic nerve, 28 - facial nerve, 29 - abducens nerve, 30 - nucleus of the facial nerve, 31 - trigeminal nerve, 32 - pons, 33 - cerebellar peduncle, 34 - oculomotor nerve [ A.K. Popov, 1968]

From the reticular formation, the root goes along the bottom of the IV ventricle, goes around the nucleus of the abducens nerve and forms a knee ( genu n. facialis). After that, it leaves the brain in the cerebellopontine angle in front of the roots of the intermediate and vestibulocochlear nerves, between the posterior edge of the bridge and the olive of the medulla oblongata. This place is called the cerebellopontine angle and is often the target of injury. The entire path of the facial nerve should be divided into the following segments (V.O. Kalina, M.A. Shuster, 1970): supranuclear, subnuclear, inside the temporal bone and outside the temporal bone.

Rice. 3. Supranuclear pathways of the facial nerve (according to Mc Gowern and Fitz-Hugh): 1 - precentral gyrus, 2 - thalamonuclear pathway (not anatomically established), 3 - nucleus of the facial nerve [V.O. Kalina, M.A. Shuster, 1970]

supranuclear segment . It is known that the motor fibers of the facial nerve, as part of the general motor pathway, begin in the lower part of the precentral gyrus (Fig. 3), go further as part of the radiant crown to the posterior leg of the internal capsule and, passing near the knee, together with the pyramidal path, enter the basal part of the Vorolieva bridge. Here, most of the fibers cross and go to the nucleus of the facial nerve on the opposite side, and some of the fibers enter the nucleus of the facial nerve on the same side. Thus, both the right and the left core n. facialis(only in its upper part) receives innervation from the cortex of both hemispheres of the brain. Subnuclear segment. The nucleus of the facial nerve is located in the ventral part of the roof of the bridge, in the rhomboid fossa, ventrolaterally from the nucleus of the abducens nerve (in colliculus facialis), where it is divided into upper and lower parts. The upper part of the nucleus, which receives bilateral cortical innervation, supplies the axons of its ganglinous cells. m. frontalis (occipito-frontalis), m. orbicularisoculi and m. corrugator supercilii, the lower part of the nucleus receives innervation only from the opposite side of the cerebral cortex. From its ganglion cells, axons go to all other mimic muscles of the face (with the exception of the muscle that lifts the upper eyelid, innervated by the oculomotor nerve), to the stylohyoid muscle, the posterior belly of the digastric muscle and platysma. These anatomical features make it possible to distinguish central (cerebral) palsy of the facial nerve, in which the upper branch is preserved (due to bilateral cortical innervation) from the peripheral one (when both the upper and lower branches are paralyzed).

Further, the facial and intermediate nerves enter the internal auditory opening and enter the facial canal (Fig. 4). Rice. four. The layout of the nerves in the canals of the temporal bone: 1 - stapedial nerve, 2 - tympanic string, 3 - tympanic plexus, 4 - connecting branch of the facial nerve with the tympanic plexus, 5 - knee node, 6 - facial nerve, 7 - intermediate nerve, 8 - vestibulocochlear nerve, 9 - connecting branch from the node of the knee to the plexus of the middle meningeal artery, 10 - large stony nerve, 11 - carotid-tympanic nerve, 12 - small stony nerve, 13 - nerve plexus of the internal carotid artery, 14 - deep stony nerve , 15 - nerve of the pterygoid canal, 16 - pterygopalatine nerves, 17 - maxillary nerve, 18 - pterygopalatine ganglion, 19 - nerve plexus of the middle meningeal artery, 20 - middle meningeal artery, 21 - ear nerve, 22 - branches of the ear node to the ear-vesicle nerve, 23 - connecting branch between the ear node and the tympanic string, 24 - chewing nerve, 25 - mandibular nerve, 26 - lingual nerve, 27 - inferior alveolar nerve, 28 - ear-temporal nerve, 29 - tympanic nerve, 30 - glossopharyngeal nerve, 31 - upper node of the vagus nerve, 32 - ear branch of the vagus nerve, 33 - connecting branch of the facial nerve with the ear branch of the vagus nerve, 34 - branches of the facial nerve to the stylohyoid muscle, 35 - branches of the facial nerve to the posterior belly of the digastric muscle , 36 - posterior auricular nerve, 37 - mastoid process [V.A. Karlov, 1991]

The right and left nuclei of the facial nerve are connected to the cerebral cortex (lower quarter of the precentral gyrus) through cortical-nuclear fibers ( fibrae corticonucleares), which is schematically shown in Figure 5. At the same time, the part of the nucleus responsible for the innervation of the muscles of the lower half of the face is connected only with the cortex of the opposite hemisphere. The other part of the nucleus, which innervates the facial muscles of the upper half of the face, has bilateral cortical-nuclear fibers and receives signals from the cortex of both hemispheres. In this regard, with a unilateral lesion of the cortical-nuclear fibers, central paralysis of the facial muscles of only the lower half of the face on the side opposite to the lesion is observed. There is a direct projection of fibers from the retina to the section of the motor nucleus of the facial nerve, which contains mononeurons to the orbicular muscle of the eye. Due to this connection, a reflex closure of the eyelids occurs with certain visual stimuli.

Rice. 5. Scheme of communication of the facial nerve nucleus with the cerebral cortex: 1 - fibers of the facial nerve to the mimic muscles of the upper face, 2 - fibers of the facial nerve to the mimic muscles of the lower face, 3 - fibers of the facial nerve to the circular muscle of the mouth (originate in the nucleus of the hypoglossal nerve ) [A.K. Popov, 1968]

Intermediate nerve ( n. intermediate) mixed. Contains parasympathetic secretory fibers to the lacrimal gland, sublingual and submandibular salivary glands, as well as sensitive taste fibers from the taste buds of the fungiform and foliate papillae of the tongue and superficial sensitivity fibers of the external auditory canal and auricle. Secretory fibers originate in the brainstem from the nerve cells of the superior salivary ( nucl. salivatorius superior) and lacrimal nuclei. Sensory nerve fibers arise from the pseudounipolar cells of the knee ganglion ( gangl. geniculi) in the canal of the facial nerve. The central processes of the geniculate node go to the node of the solitary pathway ( nucl. solitarius), which is located in the brain stem, then dorsally in the roof of the caudal part of the bridge, in the medulla oblongata, and go to the spinal nucleus of the trigeminal nerve. In the facial canal, both nerves form a common trunk, which makes two turns in accordance with the curvature of the canal. Initially, this trunk lies horizontally and is directed forward and laterally above the tympanic cavity. Then, along the facial canal, the trunk turns at a right angle posteriorly, forming a knee ( geniculum n. facialis) and knee knot ( gangl. geniculi) belonging to the intermediate nerve. Having passed above the tympanic cavity, the indicated trunk makes a second downward turn and is located behind the cavity of the middle ear. In this area, the branches of the intermediate nerve branch off. The facial nerve canal has a very pronounced tortuous course. Variants of channel sizes can be observed in any part of it. Defects can occur due to the complete closure of the walls of the facial canal during its development. In such patients, the nerve bulges into the defect (in the oval window or facial pocket). In exceptional cases, the nerve is hypoplastic or even absent. The facial nerve exits the canal through the stylomastoid foramen ( for. stylomastoideum) and enters the parotid salivary gland. At a depth of 2 cm from the outer surface, the facial nerve divides into 2-5 primary branches, which are divided into secondary ones and form the parotid plexus. It is customary to distinguish between two forms of the external structure of the parotid plexus - reticular and main. With a network-like form, the nerve trunk in the thickness of the gland is divided into many branches that have multiple connections with each other, as a result of which a narrow-braided plexus is formed. Multiple connections with the branches of the trigeminal nerve are noted. With the main form, the nerve trunk is divided into two branches (upper and lower), which give rise to several secondary branches. There are few connections between secondary branches; the plexus is broadly looped. On its way, the facial nerve gives branches along the canal, as well as when leaving it. The root of the facial nerve is supplied with blood from the inferior anterior cerebellar artery, the trunk of the facial nerve in the facial canal - from the stylomastoid, the branching area and branches of the facial nerve on the face - from the branches of the external carotid artery.

Facial nerve, p. facialis (Fig. 177), combines two nerves: the actual facial nerve, P.facialis, formed by motor nerve fibers - processes of cells of the nucleus of the facial nerve, and the intermediate nerve, P.interme- dius, containing sensitive taste and autonomic (parasympathetic) nerve fibers. Sensitive fibers end on the cells of the nucleus of the solitary pathway, motor fibers start from the motor nucleus, and vegetative fibers from the upper salivary nucleus. The nuclei of the facial nerve lie within the pons of the brain.

Coming to the base of the brain at the posterior edge of the bridge, laterally from the olive, the facial nerve, together with the intermediate and vestibulocochlear nerves, enters the internal auditory canal. In the thickness of the temporal bone, the facial nerve passes through the facial canal and exits the temporal bone through the stylomastoid foramen. In the place where there is a knee of the facial canal, the facial nerve forms a bend - knee,geniculum, and knee knot,ganglion geniculi. The knee node refers to the sensitive part of the facial (intermediate) nerve and is formed by the bodies of pseudo-unipolar neurons.

In the facial canal, the following branches depart from the facial nerve:

1 Large stony nerve, P.petrosus major, formed by preganglionic parasympathetic fibers, which are processes of cells of the superior salivary nucleus. This nerve originates from the facial in the region of the knee and exits to the anterior surface of the pyramid of the temporal bone through the cleft of the canal of the large stony nerve. Passing along the sulcus of the same name, and then through the torn hole, the large stony nerve enters the pterygoid canal and, together with the sympathetic nerve, from the internal carotid plexus [deep stony nerve, n.petrosus profundus (BNA)] is called nerve of the pterygoid canal, n.canalis pterygoidei, and as part of the latter, it approaches the pterygopalatine ganglion (see "Trigeminal nerve").

2 drum string, chorda tympani, It is formed by preganglionic parasympathetic fibers coming from the superior salivary nucleus, and sensitive (gustatory) fibers, which are peripheral processes of pseudo-unipolar cells of the knee node. The fibers originate in taste buds located in the mucosa of the anterior two-thirds of the tongue and soft palate. The tympanic string departs from the facial nerve before it exits the stylomastoid foramen, passes through the tympanic cavity without giving off branches there, and leaves it through the tympanic fissure. The tympanic string then travels forward and downward and joins the lingual nerve.

3 stapedial nerve, P.stapedius, departs from the facial nerve and innervates the stapedius muscle. After exiting the stylomastoid foramen, the facial nerve gives motor branches to the posterior belly of the supracranial muscle, to the posterior auricular muscle - the posterior auricular nerve, P.auricularis post­ rior, and to the posterior belly of the digastric muscle - digastric branch, d.digdstricus, to the stylohyoid muscle awl-hyoid branch, d.stylohyoideus. Then the facial nerve enters the parotid salivary gland and in its thickness is divided into a number of branches that connect with each other and thus form the parotid plexus, plexus parotideus [ intra- parotideus]. This plexus consists only of motor fibers. Branches of the parotid plexus:

1temporal branches,rr. temporales, go up to the temporal region and innervate the ear muscle, the frontal belly of the supracranial muscle and the circular muscle of the eye;

2zygomatic branches,rr. zygomdtici, go anteriorly and upward, innervate the circular muscle of the eye and the large zygomatic muscle;

3buccal branches,rr. buccdles, they go forward along the surface of the chewing muscle and innervate the large and small zygomatic muscles, the muscle that lifts the upper lip, and the muscle that lifts the corner of the mouth, the cheek muscle, the circular muscle of the mouth, the nasal muscle, the muscles of laughter;

4marginal branch of the lower jaw, d.margindlis mandibulae [ mandibuldris] , goes down and forward along the body of the lower jaw, innervates the muscles that lower the lower lip and corner of the mouth, as well as the chin muscle;

5cervical branch, g. sdsh, goes behind the angle of the lower jaw down the neck to the subcutaneous muscle of the neck, connects with the transverse nerve of the neck from the cervical plexus.

Facial nerve, p. facialis (Fig. 177), combines two nerves: the actual facial nerve, P.facialis, formed by motor nerve fibers - processes of cells of the nucleus of the facial nerve, and the intermediate nerve, P.interme- dius, containing sensitive taste and autonomic (parasympathetic) nerve fibers. Sensitive fibers end on the cells of the nucleus of the solitary pathway, motor fibers start from the motor nucleus, and vegetative fibers from the upper salivary nucleus. The nuclei of the facial nerve lie within the pons of the brain.

Coming to the base of the brain at the posterior edge of the bridge, laterally from the olive, the facial nerve, together with the intermediate and vestibulocochlear nerves, enters the internal auditory canal. In the thickness of the temporal bone, the facial nerve passes through the facial canal and exits the temporal bone through the stylomastoid foramen. In the place where there is a knee of the facial canal, the facial nerve forms a bend - knee,geniculum, and knee knot,ganglion geniculi. The knee node refers to the sensitive part of the facial (intermediate) nerve and is formed by the bodies of pseudo-unipolar neurons.

In the facial canal, the following branches depart from the facial nerve:

1 Large stony nerve, P.petrosus major, formed by preganglionic parasympathetic fibers, which are processes of cells of the superior salivary nucleus. This nerve originates from the facial in the region of the knee and exits to the anterior surface of the pyramid of the temporal bone through the cleft of the canal of the large stony nerve. Passing along the sulcus of the same name, and then through the torn hole, the large stony nerve enters the pterygoid canal and, together with the sympathetic nerve, from the internal carotid plexus [deep stony nerve, n.petrosus profundus (BNA)] is called nerve of the pterygoid canal, n.canalis pterygoidei, and as part of the latter, it approaches the pterygopalatine ganglion (see "Trigeminal nerve").

2 drum string, chorda tympani, It is formed by preganglionic parasympathetic fibers coming from the superior salivary nucleus, and sensitive (gustatory) fibers, which are peripheral processes of pseudo-unipolar cells of the knee node. The fibers originate in taste buds located in the mucosa of the anterior two-thirds of the tongue and soft palate. The tympanic string departs from the facial nerve before it exits the stylomastoid foramen, passes through the tympanic cavity without giving off branches there, and leaves it through the tympanic fissure. The tympanic string then travels forward and downward and joins the lingual nerve.

3 stapedial nerve, P.stapedius, departs from the facial nerve and innervates the stapedius muscle. After exiting the stylomastoid foramen, the facial nerve gives motor branches to the posterior belly of the supracranial muscle, to the posterior auricular muscle - the posterior auricular nerve, P.auricularis post­ rior, and to the posterior belly of the digastric muscle - digastric branch, d.digdstricus, to the stylohyoid muscle awl-hyoid branch, d.stylohyoideus. Then the facial nerve enters the parotid salivary gland and in its thickness is divided into a number of branches that connect with each other and thus form the parotid plexus, plexus parotideus [ intra- parotideus]. This plexus consists only of motor fibers. Branches of the parotid plexus:

1temporal branches,rr. temporales, go up to the temporal region and innervate the ear muscle, the frontal belly of the supracranial muscle and the circular muscle of the eye;

2zygomatic branches,rr. zygomdtici, go anteriorly and upward, innervate the circular muscle of the eye and the large zygomatic muscle;

3buccal branches,rr. buccdles, they go forward along the surface of the chewing muscle and innervate the large and small zygomatic muscles, the muscle that lifts the upper lip, and the muscle that lifts the corner of the mouth, the cheek muscle, the circular muscle of the mouth, the nasal muscle, the muscles of laughter;

4marginal branch of the lower jaw, d.margindlis mandibulae [ mandibuldris] , goes down and forward along the body of the lower jaw, innervates the muscles that lower the lower lip and corner of the mouth, as well as the chin muscle;

5cervical branch, g. sdsh, goes behind the angle of the lower jaw down the neck to the subcutaneous muscle of the neck, connects with the transverse nerve of the neck from the cervical plexus.

Facial nerve [interfacial nerve], n. facialis [n. intermediofacialis](VII pair) (Fig. , , , ; see fig. , , , ), - mixed nerve. The nucleus of the facial nerve, nucleus n. facialis, lies in the central part of the bridge, in the reticular formation, somewhat posterior and outward from the nucleus of the abducens nerve. From the side of the rhomboid fossa, the nucleus of the facial nerve is projected lateral to the facial tubercle (see Fig.,).

The processes of the cells that form the nucleus of the facial nerve first follow in the dorsal direction, bending around the nucleus of the abducens nerve, then, forming knee of the facial nerve, genu n. facialis, are directed ventrally and exit to the lower surface of the brain at the posterior edge of the bridge, above and lateral to the olive of the medulla oblongata.

The facial nerve itself is motor, but after joining intermediate nerve, n. intermediate, represented by sensitive and vegetative fibers (taste and secretory), becomes mixed and becomes intermediate-facial nerve.

Intermediate nerve nucleus superior salivary nucleus, nucleus salivatorius superior, - the autonomic nucleus, lies somewhat posteriorly and medially to the nucleus of the facial nerve.

The axons of the cells of this nucleus make up the bulk of the intermediate nerve.

At the base of the brain, the intermediate nerve appears along with the facial nerve. Subsequently, both nerves, together with the vestibulocochlear nerve (VIII pair), enter through the internal auditory opening of the petrous part (pyramid) of the temporal bone into the internal auditory meatus. Here the facial and intermediate nerves are connected and through field of the facial nerve, area n. facialis, enter the canal of the facial nerve. At the bend of this canal, the facial nerve forms knee, geniculum n. facialis, and thickens due to knee knot, ganglion geniculi. This node belongs to the sensitive part of the intermediate nerve.

The facial nerve repeats all the curves of the facial canal and, leaving the pyramid through the stylomastoid foramen, lies in the thickness of the parotid gland, where it divides into its main branches.

Inside the pyramid, a number of branches depart from the interfacial nerve:

1. Greater stony nerve, n. petrosus major, begins near the knee node and consists of parasympathetic fibers of the intermediate nerve. It leaves the pyramid of the temporal bone through the cleft of the canal of the large stony nerve, lies in the groove of the same name and exits the cranial cavity through a torn hole. Later, this nerve, having passed through the pterygoid canal of the sphenoid bone, in which, together with the sympathetic nerve, forms nerve of the pterygoid canal, n. canalis pterygoidei, enters the pterygopalatine fossa, reaching the pterygopalatine node. The preganglionic parasympathetic fibers of the greater stony nerve switch on the cells of this node [see Fig. "Vegetative (Autonomous) Nervous System"].
2. Connecting branch with tympanic plexus, r. communicans (cum plexu tympanico), departs from the node of the knee or from the large stony nerve and approaches the small stony nerve.
3. Stapes nerve, n. stapedius, is a very thin branch that starts from the descending part of the facial nerve, approaches the stapedius muscle and innervates it.
4. Connecting branch with the vagus nerve, r. communicans (cum nervo vago), - thin nerve, approaches the lower node of the vagus nerve.
5. Drum string, chorda tympani, is the terminal branch of the intermediate nerve. It departs from the trunk of the facial nerve slightly above the stylomastoid foramen, enters the tympanic cavity from the posterior wall, forming a small arc, concave downward, and lies between the handle of the malleus and the long leg of the anvil. Approaching the stony-tympanic fissure, the drum string leaves the skull through it. In the future, it goes down and, having passed between the medial and lateral pterygoid muscles, enters the lingual nerve at an acute angle. In its course, the drum string does not give off branches, only at the very beginning, after leaving the skull, it is connected by several branches to the ear node.

The drum string consists of two types of fibers: pre-nodal parasympathetic, which are processes of the cells of the upper salivary nucleus, and fibers of taste sensitivity - peripheral processes of the cells of the knee node. The central processes of these cells end in the nucleus of a solitary pathway.

Part of the fibers of the drum string, which are part of the lingual nerve, is sent to the submandibular and sublingual nodes as part of the nodal branches of the lingual nerve (centrifugal fibers), and the other part reaches the mucous membrane of the back of the tongue (centripetal fibers - processes of the cells of the knee node).

Having exited through the stylomastoid foramen from the pyramid of the temporal bone, the facial nerve, even before entering the thickness of the parotid gland, gives off a number of branches:

1. Posterior ear nerve, n. auricularis posterior, begins directly under the stylomastoid opening, turns backwards and upwards, goes behind the outer ear and is divided into two branches: anterior ear branch, r. auricularis, and back - occipital branch, r. occipitalis. The auricular branch innervates the posterior and superior auricular muscles, the transverse and oblique muscles of the auricle, and the antitragus muscle. The occipital branch innervates the occipital belly of the supracranial muscle and connects with the greater auricular and lesser occipital nerves of the cervical plexus and with the auricular branch of the vagus nerve.
2. Stylohyoid branch, r. stylohyoideus, may originate from the posterior auricular nerve. This is a thin nerve that goes down, enters the thickness of the muscle of the same name, having previously connected with the sympathetic plexus located around the external carotid artery.
3. Digastric branch, r. digastricus, can depart both from the posterior ear nerve and from the trunk of the facial nerve. It is located slightly below the stylohyoid branch, descends along the posterior belly of the digastric muscle and gives off branches to it. It has a connecting branch with the glossopharyngeal nerve.
4. Lingual branch, r. lingualis, unstable, is a thin nerve that envelops the styloid process and passes under the palatine tonsil. Gives a connecting branch to the glossopharyngeal nerve and sometimes a branch to the styloid muscle.

Having entered the thickness of the parotid gland, the facial nerve divides into two main branches: a more powerful upper and a smaller lower one. Further, these branches are divided into branches of the second order, which diverge radially: up, forward and down to the muscles of the face. Between these branches in the thickness of the gland, compounds are formed that make up parotid plexus, plexus parotideus.