13 cranial nerve. Damage to III, IV, VI pairs of cranial nerves

21.7. Neuralgia of the cranial and spinal nerves Neuralgia is a lesion of the peripheral segment of the nerve (branch or root), manifested by symptoms of irritation. If neuropathies are characterized by symptoms of loss of nerve function, neuralgia is characterized by symptoms of irritation.

52. Defeat of the 5th pair of cranial nerves The 5th pair of cranial nerves is mixed. The sensory pathway of a nerve is made up of neurons. The first neuron is located in the semilunar node of the trigeminal nerve, located between the layers of the dura mater on the anterior

53. Damage to the VI pair of cranial nerves Damage to the VI pair of cranial nerves is clinically characterized by the appearance of convergent strabismus. A characteristic complaint of patients is the doubling of the image, located in the horizontal plane. Frequently joins

55. Defeat of IX–X pairs of cranial nerves IX–X pair of cranial nerves mixed. The sensory pathway of the nerve is three-neural. The bodies of the first neuron are located in the nodes of the glossopharyngeal nerve. Their dendrites terminate in receptors in the posterior third of the tongue, a soft

56. Defeat of the XI-XII pair of cranial nerves. It consists of two parts: vagus and spinal. The conductive motor path is two-neuron. The first neuron is located in the lower part of the precentral gyrus. Its axons enter the brain stem, pons, oblongata

1. I pair of cranial nerves - olfactory nerve The pathway of the olfactory nerve consists of three neurons. The first neuron has two types of processes: dendrites and axons. The endings of the dendrites form olfactory receptors located in the mucous membrane of the cavity

2. II pair of cranial nerves - optic nerve The first three neurons of the visual pathway are located in the retina. The first neuron is represented by rods and cones. The second neurons are bipolar cells. Ganglion cells are the third neurons

3. III pair of cranial nerves - oculomotor nerve The central neuron is located in the cells of the cortex of the precentral gyrus of the brain. The axons of the first neurons form a cortical-nuclear pathway leading to the nuclei

4. IV pair of cranial nerves - trochlear nerve The pathway is two-neural. The central neuron is located in the cortex of the lower part of the precentral gyrus. The axons of the central neurons end in the cells of the nucleus of the trochlear nerve on both sides. The nucleus is located in

6. VI pair of cranial nerves - abducens nerve The conduction path is two-neuronal. The central neuron is located in the lower part of the cortex of the precentral gyrus. Their axons terminate on the cells of the nucleus of the abducens nerve on both sides, which are peripheral

7. VII pair of cranial nerves - facial nerve It is mixed. The motor pathway of the nerve is two-neuron. The central neuron is located in the cerebral cortex, in the lower third of the precentral gyrus. The axons of the central neurons are sent to the nucleus of the facial

8. VIII pair of cranial nerves - vestibulocochlear nerve The nerve consists of two roots: the cochlear, which is the lower, and the vestibular, which is the upper root. The cochlear part of the nerve is sensitive, auditory. It starts from the cells of the spiral node, in

9. IX pair of cranial nerves - glossopharyngeal nerve This nerve is mixed. The sensory pathway of the nerve is three-neuron. The bodies of the first neuron are located in the nodes of the glossopharyngeal nerve. Their dendrites terminate in receptors in the posterior third of the tongue, a soft

10. X pair of cranial nerves - vagus nerve It is mixed. The sensitive pathway is three-neuron. The first neurons form nodes vagus nerve. Their dendrites end in receptors on the dura mater of the posterior cranial fossa,

11. XI pair of cranial nerves - accessory nerve It consists of two parts: vagus and spinal. The conductive motor path is two-neuron. The first neuron is located in the lower part of the precentral gyrus. Its axons enter the brain stem, pons,

12. XII pair of cranial nerves - hypoglossal nerve For the most part, the nerve is motor, but it also contains a small part of the sensory fibers of the branch of the lingual nerve. The motor pathway is two-neuron. The central neuron is located in the lower cortex

1. Olfactory nerve - has no nuclei, olfactory cells are located in the mucous membrane of the olfactory region of the nasal cavity. Contains visceral sensory fibers.

The exit from the brain is from the olfactory bulb.

The exit from the skull is from the ethmoid plate of the ethmoid bone.

The nerve is a collection of 15-20 thin nerve threads, which are the central processes of the olfactory cells. They pass through holes in the ethmoid bone and then end in the olfactory bulb, which continues into the olfactory tract and triangle.

2. Optic nerve - has no nuclei, ganglionic neurocytes are located in the retina of the eyeball. Contains somatic sensory fibers.

Exit from the brain - optic chiasm at the base of the brain

Exit from the skull - optic canal

Moving away from the posterior pole of the eyeball, the nerve leaves the orbit through the optic canal and, entering the cranial cavity along with the same nerve of the other side, forms the optic chiasm, which lies in the optic sulcus of the sphenoid bone. The continuation of the optic pathway beyond the chiasm is the optic tract, ending in the lateral geniculate body and in the superior colliculus of the roof of the midbrain.

3. Oculomotor nerve - has 2 nuclei: autonomic and motor, located in the tegmentum of the midbrain (at the level of the upper mounds). Contains efferent (motor) fibers to most of the external muscles of the eyeball and parasympathetic fibers to the internal eye muscles (ciliary muscles and muscles that narrow the pupil).

The exit from the brain is from the medial sulcus of the brain stem / interpeduncular fossa / from the oculomotor sulcus.

The oculomotor nerve leaves the brain along the medial edge of the brain stem, then goes to the superior orbital fissure, through which it enters the orbit.

Entering the orbit is divided into 2 branches:

A) Superior branch - to the superior rectus muscle of the eyeball and to the muscle that lifts upper eyelid.

B) The lower branch - to the lower and medial rectus muscles of the eyeball and the lower oblique muscle of the eyeball. From the lower branch the nerve root departs to the ciliary node, carrying parasympathetic fibers for the ciliary muscle and the muscle that narrows the pupil.

4. Block nerve - has 1 motor nucleus, located in the tegmentum of the midbrain (at the level of the lower mounds). Contains only efferent (motor) fibers.

The exit from the brain is from under the lower hillocks / on the sides of the frenulum of the upper medullary velum.

The exit from the skull is the superior orbital fissure.

After leaving the brain, it goes around the brain stem laterally and through the superior orbital fissure enters the orbit, where it innervates the superior oblique muscle of the eyeball.

5. Trigeminal nerve - has 4 nuclei: 3 sensory and 1 motor nucleus. Located in the tegmentum of the midbrain, the tegmentum of the bridge, the tegmentum of the medulla oblongata. Contains afferent (sensory) fibers and efferent (motor) fibers.

The exit from the brain is the place of the bridge and the middle cerebellar peduncle.

The exit from the skull is the ophthalmic nerve - the superior orbital fissure, the maxillary nerve - a round hole, the mandibular nerve - an oval hole.

Branches of the trigeminal nerve:

1. The ophthalmic nerve enters the orbital cavity through the superior orbital fissure, but before entering it it is divided into 3 more branches:

a) The frontal nerve, runs directly anteriorly under the roof of the orbit through the supraorbital notch (or foramen) into the skin of the forehead, here it is called the supraorbital nerve, giving branches along the way into the skin of the upper eyelid and medial angle of the eye.

b) Lacrimal nerve, go to the lacrimal gland and, passing through it, ends in the skin and conjunctiva of the lateral corner of the eye. Before entering the lacrimal gland, it connects to the zygomatic nerve (from the second branch of the trigeminal nerve). Through this anastomosis, the lacrimal nerve receives secretory fibers for the lacrimal gland and supplies it with sensory fibers as well.

c) Nasociliary nerve, innervates the anterior part of the nasal cavity (anterior and posterior ethmoid nerves), the eyeball (long ciliary nerves), the skin of the medial angle of the eye, the conjunctiva and the lacrimal sac (subtrochlear nerve).

2. The maxillary nerve exits the cranial cavity through a round opening into the pterygopalatine fossa; from here, its immediate continuation is the infraorbital nerve, which goes through the inferior orbital fissure to the infraorbital groove and canal on the lower wall of the orbit and then exits through the supraorbital foramen to the face, where it splits into a bundle of branches. These branches, connecting with the branches of the facial nerve, innervate the skin of the lower eyelid, lateral surface of the nose and lower lip..

Branches of the maxillary and its continuation of the infraorbital nerves:

a) Zygomatic nerve, Inn. skin of the cheek and anterior part of the temporal region.

b) The upper alveolar nerves, in the thickness of the upper jaw, form a plexus, from which the upper alveolar branches and branches innervating the upper gums depart.

c) Nodal nerves connect the maxillary nerve with the pterygopalatine ganglion, which belongs to the autonomic nervous system.

3. The mandibular nerve, has in its composition, in addition to the sensory, the entire motor root of the trigeminal nerve. Upon exiting the skull through the foramen ovale, it divides into 2 groups of branches:

a) Muscular branches: to all the masticatory muscles, to the muscle that strains the palatine curtain, to the muscle that strains the eardrum, to the maxillohyoid muscle and the anterior belly of the digastric muscle, the corresponding nerves go.

b) Sensitive branches:

- The buccal nerve goes to the buccal mucosa.

The lingual nerve is located under the mucous membrane of the floor of the mouth.

Having given the hypoglossal nerve to the mucous membrane of the floor of the mouth, it innervates the mucous membrane of the back of the tongue for the anterior two-thirds. It is joined by a thin branch emerging from the stony-tympanic fissure, carrying parasympathetic fibers from the superior salivary nucleus (related to the facial nerve) - a drum string, which will provide innervation for the hyoid and sublingual salivary glands. The drum string also carries taste fibers from the anterior two-thirds of the tongue.

3. The lower alveolar nerve, through the mandibular foramen, together with the artery of the same name, goes into the canal of the lower jaw, where it gives branches to all lower teeth, having previously formed a plexus. At the anterior end of the mandibular canal, the nerve gives off a thick branch - the mental nerve, which emerges from the mental foramen and extends into the skin of the chin and lower lip.

4. Auriculotemporal nerve, penetrates into upper part parotid gland and goes to the temporal region, accompanying the superficial temporal artery. Gives secretory branches to the parotid gland, as well as sensory fibers to the temporomandibular joint, to the skin of the anterior part of the auricle, external ear canal and to the skin of the temple.

6. Abducens nerve - has one motor nucleus located in the pons tire. Contains only

The exit from the brain is from the groove between the bridge and the pyramid.

The exit from the skull is the superior orbital fissure.

It leaves the brain between the bridge and the pyramid, passes through the superior orbital fissure into the orbit and enters the lateral rectus muscle of the eyeball.

7. Facial nerve - incorporates motor, autonomic and sensory nuclei, located in the cover of the bridge. It contains efferent (motor), afferent (sensory) and parasympathetic fibers.

The exit from the brain is behind the middle cerebellar peduncle / cerebellopontine angle.

Exit from the skull - internal auditory canal - facial canal - stylomastoid opening.

The facial nerve enters the surface of the brain laterally along the posterior edge of the pons, next to the vestibulocochlear nerve. Then, together with the last nerve, it enters the internal auditory meatus and enters the facial canal. In the canal, the nerve first goes horizontally, heading outward, then in the area of ​​​​the gap of the canal of the large stony nerve, it turns back at a right angle and also runs horizontally along the inner wall tympanic cavity in its upper part. Having passed the limits of the tympanic cavity, the nerve again bends and descends vertically down, leaving the skull through the stylomastoid foramen. When exiting, the nerve enters the thickness of the parotid gland and is divided into terminal branches.

Gives the following branches before exiting the channel :

- The large stony nerve originates in the area of ​​the knee and exits through the gap of the canal of the large stony nerve; then it goes along the groove of the same name on the anterior surface of the pyramid of the temporal bone, passes into the pterygoid canal along with the sympathetic nerve, the deep stony nerve, forming with it the nerve of the pterygopalatine canal and reaches the pterygopalatine node.

The nerve is interrupted at the node and its fibers as part of the posterior nasal and palatine nerves go to the glands of the mucous membrane of the nose and palate; part of the fibers in the zygomatic nerve through connections with the lacrimal nerve reaches the lacrimal gland. The posterior nasal branches also give off the nasopalatine nerve to the glands of the mucous membrane of the hard palate. The palatine nerves innervate the glands of the mucous membrane of the soft and hard palate.

- stapedial nerve, innervates the corresponding muscle.

- drum string, having separated from the facial nerve in the lower part of the facial canal, penetrates into the tympanic cavity, lies there on the medial surface of the tympanic membrane, and then leaves through the stony-tympanic fissure; leaving the gap to the outside, it joins the lingual nerve, supplying the anterior two-thirds of the tongue with taste fibers. The secretory part approaches the submandibular node and, after a break in it, supplies the submandibular and sublingual salivary glands with secretory fibers.

After exiting the stylomastoid foramen, it gives the following branches:

- Posterior ear nerve, innervates the posterior ear muscle and the occipital abdomen of the cranial vault.

- Digastric branch, innervates the posterior belly of the digastric muscle and the stylohyoid muscle.

- parotid plexus, formed by numerous branches to the facial muscles of the face:

Temporal branches - Inn. upper and anterior ear muscles, frontal belly of the cranial vault, circular muscle of the eye;

Zygomatic branches - inn. circular muscle of the eye and zygomatic muscle;

Buccal branches - to the muscles of the circumference of the mouth and nose;

Marginal mandibular branch - a branch that runs along the edge of the lower jaw to the muscles of the chin and lower lip;

Neck branch - inn. superficial neck muscle.

Intermediate nerve, is a mixed nerve. It contains afferent (gustatory) fibers going to its sensory nucleus (single nucleus) and efferent (secretory, parasympathetic) fibers coming from its autonomic (secretory) nucleus (superior salivary nucleus). The intermediate nerve leaves the brain as a thin trunk between the facial and vestibulocochlear nerves, after passing some distance, joins the facial nerve, becomes its integral part. Further, it passes into a large stony nerve. Conducts sensitive impulses from taste buds anterior part of the tongue and soft palate. Secretory parasympathetic fibers are sent to the submandibular and sublingual salivary glands.

8. Vestibulocochlear nerve, has in its composition 6 sensitive nuclei located in the cover of the bridge. It contains only afferent (sensory) fibers.

The exit from the brain is lateral to the facial nerve, from the cerebellopontine angle.

The exit from the skull is the internal auditory meatus.

It consists of two parts: the vestibular part and the cochlear part. Sensory fibers are responsible for the specific innervation of the organ of hearing (fibers from the cochlear nuclei; cochlear part) and the specific innervation of the balance organ (fibers from the vestibular nuclei; vestibular part).

9. The glossopharyngeal nerve has 3 different nuclei: motor, autonomic and sensory, located in the tegmentum of the medulla oblongata. It contains efferent (motor) fibers, parasympathetic fibers and afferent (motor) fibers.

Out of the brain - lateral to the two previous nerves / from the posterolateral groove, behind the olive.

The glossopharyngeal nerve emerges with its roots from the medulla oblongata behind the olive, above the vagus nerve, and together with the latter leaves the skull through the jugular foramen. Within the jugular foramen, the sensitive part of the nerve forms the upper node, and upon exiting the hole, the lower node, which lies on the lower surface of the temporal bone pyramid. The nerve descends, first between the internal jugular vein and the internal carotid artery, and then goes around the stylohyoid muscle behind and along the lateral side of this muscle it approaches the root of the tongue in a gentle arc, where it divides into terminal branches.

Branches of the glossopharyngeal nerve:

The tympanic nerve departs from the lower node and enters the tympanic cavity, where it forms the tympanic plexus, to which branches also come from the sympathetic plexus with the internal carotid artery. This plexus innervates the mucous membrane of the tympanic cavity and auditory tube. After exiting the tympanic cavity through the upper wall, it will be called the small stony nerve, which passes to the groove of the same name, along the anterior surface of the temporal bone pyramid and reaches the ear node.

Parasympathetic secretory fibers for the parotid gland are brought to this node; after switching fibers at this node, the postganglionic fibers go as part of the auriculotemporal nerve (the third branch of the trigeminal nerve).

The stylo-pharyngeal branch innervates the muscle of the same name.

Tonsil branches innervate the mucous membrane of the palatine tonsils and arches.

Pharyngeal branches go to the pharyngeal plexus.

The lingual branches, the terminal branches of the glossopharyngeal nerve, are sent to the mucous membrane of the posterior third of the tongue, supplying sensory fibers, among which the taste fibers also pass.

Branch of the carotid sinus, sensory nerve to the carotid sinus.

10. The vagus nerve has 3 different nuclei: motor, autonomic and sensory nuclei, located in the tegmentum of the medulla oblongata. It contains efferent (motor), afferent (sensory) and parasympathetic fibers.

The exit from the brain is from the posterolateral groove, behind the olive.

The exit from the skull is the jugular foramen.

Fibers of all kinds exit the medulla oblongata in its posterior lateral groove, below the glossopharyngeal nerve, in 10-15 roots, which form a thick nerve trunk that leaves the cranial cavity through the jugular foramen. In the jugular foramen, the sensitive part of the nerve forms top node, and after leaving the hole bottom node. Upon exiting the cranial cavity, the vagus nerve trunk descends to the neck behind the vessels in the groove, first between the internal jugular vein and the internal carotid artery, and then between the same vein and the common carotid artery.

The vagus nerve then enters through the superior foramen chest into the chest cavity where its right trunk is located in front of the subclavian artery, and the left one is on the front side of the aortic arch. Going down, both vagus nerves bypass the root of the lung behind on both sides and accompany the esophagus, forming plexuses on its walls, moreover, the left nerve - passes along the front side, and the right - along right side. Together with the esophagus, both vagus nerves penetrate through esophageal opening into the abdominal cavity, where they form plexuses on the walls of the stomach.

Branches of the vagus nerves:

A) At the head:

Meningeal branch - Inn. hard shell of the brain in the region of the posterior cranial fossa.

Ear branch - Inn. the back wall of the external auditory canal and part of the skin of the auricle.

B) In the neck:

The pharyngeal nerves, together with the branches of the glossopharyngeal nerve, form the pharyngeal plexus; pharyngeal branches of the vagus nerve innervate constrictors of the pharynx, muscles of the palatine arches and soft palate; the pharyngeal plexus also provides sensory innervation to the pharyngeal mucosa.

The superior laryngeal nerve supplies sensory fibers to the mucous membrane of the larynx above the glottis, part of the root of the tongue and epiglottis, and motor fibers - part of the muscles of the larynx and the lower constrictor of the pharynx.

3. Superior and inferior cardiac cervical branches, form the heart plexus.

B) In the chest:

Recurrent laryngeal nerve, on the right side, this nerve goes around from below and behind subclavian artery, and on the left - also from below and behind the aortic arch and then rises upward in the groove between the esophagus and trachea, give numerous esophageal and tracheal branches. The end of the nerve, called the lower laryngeal nerve, innervates part of the muscles of the larynx, its mucous membrane below the vocal folds, the mucous membrane of the root of the tongue near the epiglottis, as well as the trachea, pharynx and esophagus, thyroid and thymus glands, lymph nodes of the neck, heart and mediastinum.

cardiac pectoral branches, go to the cardiac plexus.

Bronchial and tracheal branches, parasympathetic, together with the branches of the sympathetic trunk form the pulmonary plexus on the walls of the bronchi. Due to the branches of this plexus, the muscles and glands of the trachea and bronchi are innervated, and in addition, it contains sensory fibers for the trachea, bronchi and lungs.

Esophageal branches go to the wall of the esophagus.

D) in the abdomen:

The plexus of the vagus nerves, going through the esophagus, continues to the stomach, forming pronounced trunks (anterior and posterior). The continuation of the left vagus nerve, descending from the anterior side of the esophagus to the anterior wall of the stomach, forms anterior gastric plexus, located mainly along the lesser curvature of the stomach, from which depart mixed with sympathetic branches anterior gastric branches.

Continuation of the right vagus nerve descending back wall esophagus, is the posterior gastric plexus, in the region of the lesser curvature of the stomach, which gives off the posterior gastric branches. In addition, most of the fibers of the right vagus nerve in the form of celiac branches go along with the left gastric artery to the celiac trunk, and from here along the branches of the vessels, along with the sympathetic plexuses, to the liver, spleen, pancreas, kidneys, small and large intestine to the sigmoid.

11. Accessory nerve, has 1 motor nucleus, located in the tegmentum of the medulla oblongata. It contains only efferent (motor) fibers.

The exit from the brain is from the same furrow as the vagus nerve, below it.

The exit from the skull is the jugular foramen.

According to the nuclei in the nerve, the cerebral and spinal parts are distinguished. cerebral part emerges from the medulla oblongata below the vagus nerve . spinal part accessory nerve is formed between the anterior and posterior roots of the spinal nerves (from 2-5) and partly from the anterior roots of the top three cervical nerves, rises in the form of a nerve trunk up and joins the cerebral part. The accessory nerve, together with the vagus nerve, exits the cranial cavity through the jugular foramen and innervates the trapezius muscle of the back and the sternocleidomastoid muscle. The cerebral portion of the accessory nerve, together with the recurrent laryngeal nerve, innervates the muscles of the larynx.

12. The hypoglossal nerve has one motor nucleus located in the tegmentum of the medulla oblongata. Contains only efferent (motor) fibers.

The exit from the brain is the anterolateral sulcus of the medulla oblongata, between the pyramid and the olive.

The exit from the skull is the hyoid canal.

Appearing at the base of the brain between the pyramid and the olive with several roots, the nerve then passes in the canal of the same name of the occipital bone, descends down the lateral side of the internal carotid artery, passes under the posterior belly of the digastric muscle and goes in the form of an arc, convex downwards, along the lateral surface of the hyoid-lingual muscle. One of the branches of the nerve, the upper root, goes down, connects with the lower root of the cervical plexus and forms a cervical loop with it. From this loop, the muscles located below the hyoid bone are innervated. + Innervates the derivatives of the occipital myotomes - all the muscles of the tongue.

11.4.1. General characteristics of the cranial nerves.

11.4.2. [-IV pair of cranial nerves.

11.4.3. The main branches of the V-VIII pairs of cranial nerves.

11.4.4. Areas of innervation of the IX-XII pairs of cranial nerves.

OBJECTIVE: To know the name, topography of the nuclei and the functions of the twelve pairs of cranial nerves.

Represent the areas of innervation of the cranial nerves.

Be able to show on the skeleton of the head the exit points of the cranial nerves from the cranial cavity.

11.4.1. The cranial nerves (nervi craniales, seu encephalici) are the nerves extending from the brain stem. They in it either start from the corresponding nuclei, or end. There are 12 pairs of cranial nerves. Each pair has a serial number, denoted by a Roman numeral, and a name. Serial number reflects the sequence of nerve exit:

I pair - olfactory nerves (nervi olfactorii);

And a couple - the optic nerve (nervus opticus);

III pair - oculomotor nerve (nervus oculomotorius);

IV pair - trochlear nerve (nervus trochlearis);

Trigeminal nerve (nervus trigeminus);

Abducens nerve (nervus abducens);

Facial nerve (nervus facialis);

Vestibulocochlear nerve (nervus vestibulocochlearis);

Glossopharyngeal nerve (nervus glossopharyngeus);

Vagus nerve (nervus vagus);

Accessory nerve (nervus accessorius);

Hypoglossal nerve (nervus hypoglossus).

Upon leaving the brain, the cranial nerves go to the corresponding openings at the base of the skull, through which they leave the cranial cavity and branch in the head and neck, and the vagus nerve (X pair) also in the chest and abdominal cavities.

All cranial nerves differ in the composition of nerve fibers and in function. Unlike the spinal nerves, which are formed from the anterior and posterior roots, are mixed and only on the periphery are divided into sensory and motor nerves, the cranial nerves are one of these two roots, which never join together in the head region. The olfactory and optic nerves develop from outgrowths of the anterior cerebral bladder and are processes of cells that lie in the mucous membrane of the nasal cavity (organ of smell) or in the retina of the eye. The remaining sensory nerves are formed by eviction from the emerging brain of young nerve cells, the processes of which form sensory nerves (for example, the vestibulocochlear nerve) or sensory (afferent) fibers mixed nerves(trigeminal, facial, glossopharyngeal, vagus nerves). Motor cranial nerves (trochlear, abducens, accessory, hypoglossal nerves) were formed from motor (efferent) nerve fibers, which are processes of motor nuclei that lie in the brain stem. Thus, some of the cranial nerves are sensitive: I, II, VIII pairs, others: III, IV, VI, XI and XII pairs are motor, and the third: V, VII, IX, X pairs are mixed. As part of the III, VII, IX and X pairs of nerves, along with other nerve fibers, parasympathetic fibers pass.

11.4.2. I pair - olfactory nerves, sensitive, formed by long processes (axons) of olfactory cells, which are located in the mucous membrane of the olfactory region of the nasal cavity. Single nerve trunk olfactory nerve fibers do not form, but are collected in the form of 15-20 thin olfactory nerves (threads), which pass through the holes of the ethmoid plate of the same bone, enter the olfactory bulb and contact the mitral cells (second neuron). Axons of mitral cells in the thickness of the olfactory tract are directed to the olfactory triangle, and then as part of the lateral
the stripes run into the parahippocampal gyrus and into the hook, which houses the cortical center of smell.

II pair - optic nerve, sensitive, formed by axons of ganglion cells of the retina of the eye. It is a conductor of visual impulses that arise in the light-sensitive cells of the eye: rods and cones and are transmitted first to bipolar cells (neurocytes), and from them to ganglionic neurocytes. The processes of ganglion cells form the optic nerve, which from the orbit through the optic canal of the sphenoid bone penetrates into the cranial cavity. There it immediately forms a partial decussation - chiasm with the optic nerve of the opposite side and continues into the optic tract. The optic tracts approach the subcortical visual centers: the nuclei of the lateral geniculate bodies, the thalamic cushions, and the superior colliculi of the midbrain roof. The nuclei of the superior hillocks are connected with the nuclei of the oculomotor nerve (the accessory parasympathetic nucleus of N.M. Yakubovich - through it pupillary reflex constriction of the pupil in bright light and accommodation of the eye) and with the nuclei of the anterior horns through the operculospinal tract (for the implementation of an orienting reflex to sudden light stimuli). From the nuclei of the lateral geniculate bodies and pillows of the thalamus, the axons of the 4th neuron follow to the occipital lobe of the cortex (to the spur groove), where higher analysis and synthesis of visual perceptions.

III pair - the oculomotor nerve consists of motor somatic and efferent parasympathetic nerve fibers. These fibers are the axons of the motor nucleus and the accessory parasympathetic nucleus of N.M. Yakubovich, located at the bottom of the cerebral aqueduct - at the level of the upper mounds of the roof of the midbrain. The nerve exits the cranial cavity through the superior orbital fissure into the orbit and divides into two branches: superior and inferior. The motor somatic fibers of these branches innervate 5 striated muscles of the eyeball: the superior, inferior and medial rectus, inferior oblique and the muscle that lifts the upper eyelid, and the parasympathetic fibers - the muscle that narrows the pupil, and the ciliary, or ciliary, muscle (both smooth). Parasympathetic fibers on the way to the muscles switch in the ciliary node, which lies in the posterior part of the orbit.

IV pair - trochlear nerve, motor, thin, starts from the nucleus located at the bottom of the aqueduct of the brain at the level of the lower mounds of the roof of the midbrain. The nerve passes into the orbit through the superior orbital fissure above and lateral to the oculomotor nerve, reaches the superior oblique muscle of the eyeball and innervates it.

11.4.3. V pair - trigeminal nerve, mixed, the thickest of all cranial nerves. Consists of sensory and motor nerve fibers. Sensitive nerve fibers are the dendrites of neurons of the trigeminal (Gasserov) node, which is located at the top of the pyramid of the temporal bone. These nerve fibers (dendrites) form 3 branches of the nerve: the first is the ophthalmic nerve, the second is the maxillary nerve, and the third is the mandibular nerve. The central processes (axons) of the neurons of the trigeminal ganglion make up the sensory root of the trigeminal nerve, which goes to the brain to the sensory nuclei of the pons and medulla oblongata (one nucleus). From these nuclei, the axons of the second neurons follow to the thalamus, and from it the axons of the third neurons to the lower sections of the postcentral gyrus of the cerebral cortex.

The motor fibers of the trigeminal nerve are the axons of the neurons of its motor nucleus located in the bridge. These fibers exit the brain to form a motor root, which, bypassing the trigeminal ganglion, joins the mandibular nerve. Thus, the ophthalmic and maxillary nerves are purely sensitive, and the mandibular is mixed. Along the way, parasympathetic fibers from the facial or glossopharyngeal nerve join each of the branches, which terminate in the lacrimal and salivary glands. These fibers are postganglionic processes (axons) of the cells of the parasympathetic part of the autonomic nervous system, which settled in these areas during embryogenesis from the rhomboid brain (pterygopalatine, ear nodes).

1) ophthalmic nerve enters the orbit through the superior orbital fissure and divides into the lacrimal, frontal, and nasociliary nerves. Gives sensitive and parasympathetic (from the VII pair) branches to the lacrimal gland, eyeball, skin of the upper eyelid, forehead, conjunctiva of the upper eyelid, nasal mucosa, frontal, sphenoid and ethmoid sinuses.

2) The maxillary nerve exits the cranial cavity through a round hole into the pterygopalatine fossa, where the infraorbital and zygomatic nerves depart from it. The infraorbital nerve enters the orbital cavity through the inferior orbital fissure, from there it exits through the infraorbital canal to the anterior surface of the upper jaw. Along the way, in the infraorbital canal, it gives off branches for the innervation of the teeth and gums of the upper jaw; on the face, it innervates the skin of the lower eyelid, nose, and upper lip. The zygomatic nerve also enters the orbit through the inferior orbital fissure, giving off parasympathetic secretory fibers (from the VII pair) to the lacrimal gland along the course of the ophthalmic nerve. Then it enters the zygomatic-orbital foramen of the zygomatic bone and divides into two branches. One enters the temporal fossa (through the zygomatic-temporal opening of the zygomatic bone) and innervates the skin of the temporal region and the lateral angle of the eye, the other appears on the anterior surface of the zygomatic bone (through the zygomatic-facial opening of the zygomatic bone), innervating the skin of the zygomatic and buccal regions. As part of the terminal branches of the maxillary nerve from the pterygopalatine node, the parasympathetic fibers of the facial nerve approach the mucous membrane and glands of the nasal cavity, hard and soft palate, and pharynx.

3) The mandibular nerve exits the cranial cavity through the foramen ovale into the infratemporal fossa. With motor branches, it innervates all the chewing muscles, muscles that strain the palatine curtain, the tympanic membrane, the maxillohyoid muscle and the anterior belly of the digastric muscle. Sensory fibers are part of the five main branches that innervate mainly the skin of the lower face and temporal region.

a) The meningeal branch returns to the cranial cavity through the spinous foramen (accompanying the middle meningeal artery) to innervate the dura mater in the region of the middle cranial fossa.

b) The buccal nerve innervates the skin and mucous membrane of the cheek.

c) The ear-temporal nerve innervates the skin of the auricle, the external auditory canal, the tympanic membrane and the skin of the temporal region. It contains secretory parasympathetic fibers of the glossopharyngeal nerve to the parotid salivary gland, switching in the ear node at the foramen ovale from the small petrosal nerve.

d) The lingual nerve perceives the general sensitivity of the mucous membrane of the anterior two-thirds of the tongue and the mucous membrane of the oral cavity. Parasympathetic fibers of the tympanic string from the facial nerve are attached to the lingual nerve for secretory innervation of the submandibular and sublingual salivary glands.

e) The inferior alveolar nerve is the largest of all branches of the mandibular nerve. It enters the mandibular canal through the foramen of the same name, innervates the teeth and gums of the lower jaw, and then exits through the mental foramen and innervates the skin of the chin and lower lip.

VI pair - the efferent nerve, motor, is formed by the axons of the motor cells of the nucleus of this nerve, which lies in the cover of the bridge. It enters the orbit through the superior orbital fissure and innervates the lateral (external) rectus muscle of the eyeball.

VII pair - the facial, or intermediate facial, nerve, mixed, combines two nerves: the actual facial, formed by the motor fibers of the cells of the nucleus of the facial nerve, and the intermediate nerve, represented by sensitive taste and autonomic (parasympathetic) fibers and the corresponding nuclei. All nuclei of the facial nerve lie within the pons of the brain. The facial and intermediate nerves leave the brain nearby, enter the internal auditory meatus and join into one trunk - the facial nerve, which passes in the canal of the facial nerve. In the facial canal of the pyramid of the temporal bone, 3 branches depart from the facial nerve:

1) a large stony nerve that carries parasympathetic fibers to the pterygopalatine ganglion, and from there postganglionic secretory fibers as part of the zygomatic and other nerves from the second branch of the trigeminal nerve approach the lacrimal gland, glands of the mucous membrane of the nasal cavity, mouth and pharynx;

2) the drum string passes through the tympanic cavity and, leaving it, joins the lingual nerve from the third branch of the trigeminal nerve; it contains taste fibers for the taste buds of the body and tip of the tongue (anterior two-thirds) and secretory parasympathetic fibers for the submandibular and sublingual salivary glands;

3) the stapedial nerve innervates the stapedial muscle of the tympanic cavity.

Having given its branches in the facial canal, the facial nerve leaves it through the stylomastoid foramen. After exiting, the facial nerve gives off motor branches to the posterior belly of the supracranial muscle, to the posterior auricular muscle, to the posterior belly of the digastric muscle, and to the stylohyoid muscle. Then the facial nerve enters the parotid salivary gland and in its thickness fan-like disintegrates, forming the so-called large crow's foot - the parotid plexus. This plexus consists only of motor fibers that innervate all the mimic muscles of the head and part of the muscles of the neck (subcutaneous muscle of the neck, etc.).

VIII pair - vestibulocochlear nerve, sensitive, formed by sensitive nerve fibers coming from the organ of hearing and balance. It consists of two parts: vestibular and cochlear, which are different in their functions. The vestibular part is the conductor of impulses from the static apparatus embedded in the vestibule and semicircular ducts of the labyrinth of the inner ear, and the cochlear part conducts auditory impulses from the spiral organ located in the cochlea, which perceives sound stimuli. Both parts are composed of bipolar cells ganglions located in the pyramid of the temporal bone. The peripheral processes (dendrites) of the cells of the vestibular ganglion end on the receptor cells of the vestibular apparatus in the vestibule and ampullae of the semicircular ducts, and the cells of the cochlear ganglion end on the receptor cells of the spiral organ in the cochlea of ​​the inner ear. The central processes (axons) of these nodes are connected in the internal auditory canal to the vestibulocochlear nerve, which exits the pyramid through the internal auditory opening and ends in the nuclei of the bridge (in the region of the vestibular field of the rhomboid fossa). The axons of the cells of the vestibular nuclei (the second neuron) are sent to the nuclei of the cerebellum and to the spinal cord, forming the vestibulo-spinal tract. Part of the fibers of the vestibular part of the vestibulocochlear nerve goes directly to the cerebellum, bypassing the vestibular nuclei. The vestibular part of the vestibulocochlear nerve is involved in the regulation of the position of the head, trunk and limbs in space, as well as in the system of coordination of movements. The axons of the cells of the anterior and posterior cochlear nuclei of the pons (the second neuron) are sent to the subcortical centers of hearing: the medial geniculate body and the inferior colliculus of the roof of the midbrain. Part of the fibers of the cochlear nuclei of the bridge ends in the medial geniculate body, where the third neuron is located, which transmits impulses along its axon to the cortical center of hearing, located in the superior temporal gyrus (R. Geschl's gyrus). Another part of the fibers of the cochlear nuclei of the pons passes in transit through the medial geniculate body, and then through the handle of the inferior colliculus enters its nucleus, where it ends. Here begins one of the extrapyramidal tracts (cover-spinal tract), which transmits impulses from the lower hillocks of the midbrain roof plate to the cells of the motor nuclei of the anterior horns spinal cord.

11.4.4. IX pair - glossopharyngeal nerve, mixed, contains sensory, motor and autonomic nerve fibers, but sensory fibers predominate in it. The nuclei of the glossopharyngeal nerve are located in the medulla oblongata: motor - a double nucleus, common with the vagus nerve; vegetative (parasympathetic) - lower salivary nucleus; the nucleus of a solitary pathway, where sensory nerve fibers end. The fibers of these nuclei form the glossopharyngeal nerve, which exits the cranial cavity through the jugular foramen along with the vagus and accessory nerves. At the jugular foramen, the glossopharyngeal nerve forms two sensitive nodes: the upper and the larger lower. The axons of the neurons of these nodes end in the nucleus of the solitary tract of the medulla oblongata, and the peripheral processes (dendrites) go to the receptors of the mucous membrane of the posterior third of the tongue, to the mucous membrane of the pharynx, middle ear, as well as to the carotid sinuses and glomerulus. Main branches of the glossopharyngeal nerve:

1) the tympanic nerve provides sensitive innervation of the mucous membrane of the tympanic cavity and the auditory tube; through the terminal branch of this nerve - a small stony nerve from the lower salivary nucleus, parasympathetic secretory fibers are brought to the parotid salivary gland. After a break in the ear node, secretory fibers approach the gland as part of the ear-temporal nerve from the third branch of the trigeminal nerve;

2) tonsil branches - to the mucous membrane of the palatine arches and tonsils;

3) sinus branch - to the carotid sinus and carotid glomerulus;

4) a branch of the stylo-pharyngeal muscle for its motor innervation;

5) the pharyngeal branches, together with the branches of the vagus nerve and the branches of the sympathetic trunk, form the pharyngeal plexus;

6) the connecting branch joins the ear branch of the vagus nerve.

The terminal branches of the glossopharyngeal nerve - lingual branches provide sensory and gustatory innervation of the mucous membrane of the posterior third of the tongue.

X pair - the vagus nerve, mixed, is the longest of the cranial nerves. It contains sensory, motor and parasympathetic fibers. However, parasympathetic fibers make up the bulk of the nerve. According to the composition of the fibers and the area of ​​innervation, the vagus nerve is the main parasympathetic nerve. The nuclei of the vagus nerve (sensory, motor and parasympathetic) are located in the medulla oblongata. The nerve exits the cranial cavity through the jugular foramen, where the sensitive part of the nerve has two nodes: upper and lower. The peripheral processes (dendrites) of the neurons of these nodes are part of the sensory fibers branching in various internal organs where there are sensitive nerve endings - visceroreceptors. The central processes (axons) of the neurons of the nodes are grouped into a bundle, which ends in the sensory nucleus of the solitary pathway of the medulla oblongata. One of the sensory branches, the depressor nerve, terminates in receptors in the aortic arch and plays an important role in the regulation of blood pressure. Other thinner sensitive branches of the vagus nerve innervate part of the hard shell of the brain and the skin of the external auditory canal and auricle.

Motor somatic fibers innervate the muscles of the pharynx, soft palate (with the exception of the muscle that strains the palatine curtain) and the muscles of the larynx. Parasympathetic (efferent) fibers emanating from the autonomic nucleus of the medulla oblongata innervate the organs of the neck, chest and abdominal cavities, with the exception of sigmoid colon and pelvic organs. Impulses flow along the fibers of the vagus nerve, which slow down the rhythm of the heartbeat, dilate blood vessels, constrict the bronchi, increase peristalsis and relax the sphincters of the digestive tract, increase secretion digestive glands etc.

Topographically, the vagus nerve is divided into 4 sections: head, cervical, thoracic and abdominal.

Branches depart from the head to the hard shell of the brain (meningeal branch) and to the skin of the posterior wall of the external auditory canal and part of the auricle (ear branch).

The pharyngeal branches depart from the cervical region (to the pharynx and muscles of the soft palate), the upper cervical cardiac branches (to the cardiac plexus), the superior laryngeal and recurrent laryngeal nerves (to the muscles and mucous membrane of the larynx, to the trachea, esophagus, cardiac plexus).

From the thoracic region depart the thoracic cardiac branches - to the cardiac plexus, bronchial branches - to the pulmonary plexus, esophageal branches - to the esophageal plexus.

The abdominal region is represented by the anterior and posterior vagus trunks, which are branches of the esophageal plexus. The anterior vagus trunk extends from the anterior surface of the stomach and gives off branches to the stomach and liver. The posterior vagus trunk is located on the posterior wall of the stomach and gives off branches to the stomach and celiac plexus, then to the liver, pancreas, spleen, kidney, small intestine and part of the large intestine (to the descending colon).

XI pair - accessory nerve, motor, has two nuclei: one lies in the medulla oblongata, and the other in the spinal cord. The nerve begins with several cranial and spinal roots. The latter rise up, enter the cranial cavity through the foramen magnum, merge with the cranial roots and form the trunk of the accessory nerve. This trunk, coming into the jugular foramen, is divided into two branches. One of them, the inner branch, joins the trunk of the vagus nerve, and the other, the outer branch, after exiting the jugular foramen, goes down and innervates the chest but the clavicular-mastoid and trapezius muscles.

XII pair - hypoglossal nerve, motor. Its nucleus is located in the medulla oblongata. The nerve emerges as numerous roots in the groove between the pyramid and the olive. It leaves the cranial cavity through the canal of the hyoid nerve of the occipital bone, then arcuately goes to the tongue, innervating all its muscles and partially some muscles of the neck. One of the branches of the hypoglossal nerve (descending) forms, together with the branches of the cervical plexus, the so-called cervical loop (loop of the hypoglossal nerve). The branches of this loop innervate the muscles of the neck, which lie below the hyoid bone.

Differences between cranial nerves and spinal nerves:

1. The cranial nerves start from the brain.

2. Cranial nerves 12 pairs.

3. The sensitive part of the cranial nerves has a sensitive ganglion.

4. According to their function, cranial nerves are divided into: sensory, motor and mixed.

I, II, VIII - sensitive;

IV, VI, XI, XII - motor;

III, V, VII, IX, X - mixed.

I pair of cranial nerves– n.n. olfactorii start from receptors located in the regio olfactoria of the mucous membrane of the nasal cavity with nerve filaments (fila olfactoria). Fila olfactoria pass through the openings of the lamina cribrosa and terminate in the olfactory bulbs, continuing into olfactory pathways, which are sent to the subcortical and cortical olfactory centers.

2nd pair of cranial nerves– n. opticus. Receptors are located on the retina (rods and cones, bipolar and ganglion cells), the fibers from these cells form the optic nerve (n. opticus), the medial fibers of which intersect (chiasma opticus) in sulcus chiasmatis on the body of the sphenoid bone. After the intersection, the optic tract (tractus opticus) is formed, which goes to the subcortical centers of vision (colliculi superiores of the roof of the midbrain, corpus geniculatum laterale, pulvinar thalami). From the colliculi superiores, the tractus tecto-spinalis goes to the motor nuclei of the anterior horns of the spinal cord, providing motor, protective, unconditioned reflex responses to strong visual stimuli. From the corpus geniculatum laterale, pulvinar thalami, impulses go to the cortical centers of vision, which are the occipital lobes of the hemispheres around the spur groove (sulcus calcarinus).

III pair of cranial nerves- oculomotor nerve (n. oculomotorius).

It has 2 nuclei: motor and parasympathetic.

The nuclei are located in the tegmentum of the midbrain. The nerve exits the brain along the medial edge of the cerebral peduncles. The function of the nerve is mixed, as it contains motor and parasympathetic fibers. Through fissura orbitalis superior enters the orbit and divides into 2 branches:

The upper one is ramus superior and the lower one is ramus inferior. Ramus superior innervates: m. rectus superior, m. levator palpebrae superiores. Ramus inferior innervates: m. rectus inferior, m. rectus medialis, m. oblique inferior.

Parasympathetic fibers as part of the lower branch reach the parasympathetic ciliary ganglion, which is located in the orbit (ganglion ciliare), postganglionic fibers that innervate m. sphincter pupillae, m. ciliaris.

IV pair - trochlear nerve(n. trochlearis). It has one motor nucleus - n. motorius, which is embedded in the tegmentum of the midbrain at the level of the inferior tubercles of the quadrigemina. It comes out of the brain around the lateral side of the legs of the brain. Through the fissura orbitalis superior passes into the orbit and innervates m. obliqus superior of the eyeball.

VI pair - abducens nerve (n. abducens). It has one motor nucleus, which is embedded in the thickness of the facial tubercles on the dorsal surface of the bridge. Through the fissura orbitalis superior passes into the orbit and innervates m. rectus lateralis of the eyeball.

V pair - trigeminal nerve (n. trigeminus). It has three sensory nuclei and one motor. The nuclei are laid in the bridge, and one is sensitive in the tegmentum of the midbrain. The nerve is mixed in function, as it contains sensory and motor fibers. The fibers of the motor nucleus form the motor root - radix motoria. The sensitive part of the nerve has a ganglion - ganglion trigeminale. In this ganglion are the bodies of sensitive cells. The central processes of these cells connect with the sensory nuclei of the nerve and form a sensitive root - radix sensoria. And the peripheral processes go as part of the branches of the trigeminal nerve.

After the trigeminal ganglion trigeminal nerve gives off three branches:

1. First branch - ophthalmic nerve (n. ophthalmicus).

2. Second branch - maxillary nerve (n. maxillaris).

3. Third branch - mandibular nerve (n. mandibularis).

The first two branches are sensitive in function, and the third branch is mixed, as it contains sensory and motor fibers.

Each of the three branches gives off sensitive branches to the dura mater.

Optic nerve (n. ophthalmicus) through fissura orbitalis superior enters the orbit and gives off branches:

N. frontalis exits the orbit through the incisura supraorbitalis and continues into n. supraorbitalis and innervates the skin of the upper eyelid and forehead from the incision of the eyes.

N. lacrimalis - sensitive innervation of the lacrimal gland, skin and conjunctiva of the lateral corner of the eye.

N. nasociliaris gives branches:

N. ciliaris longi - sensitive innervation of the membranes of the eyeball.

N. ethmoidalis anterior et posterior through the channels of the same name pass into the nasal cavity and innervate the mucous membrane of the nasal cavity.

N. infratrochlearis innervates the skin and conjunctiva of the medial angle of the eye.

Maxillary nerve (n. maxillaris) goes through foramen rotundum into the pterygopalatine fossa, then through the lower orbital fissure into the orbit and passes into the canalis infraorbitalis, Foramen infraorbitale to the anterior surface of the upper jaw. In the eye socket n. maxillaris changes its name, it is called the infraorbital nerve (n. infraorbitalis), which innervates the skin of the lower eyelid, external nose and upper lip.

N. maxillaris in the pterygopalatine fossa gives branches:

n. zygomaticus goes into the orbit through the lower orbital fissure (fissura orbitalis inferior), exits through the foramen infraorbitalis, zygomaticofacialis et zygomaticotemporalis and innervates the skin of the cheek and temporal region.

n.n. alveolares superiores in the thickness of the upper jaw form a plexus (plexus dentalis superior), from which rami dentalis superior depart to the teeth of the upper jaw and rami gingivalis superior to the gums of the upper jaw.

· sensitive branches through the foramen sphenopalatinum to the mucous membrane of the nasal cavity.

· sensitive branches through the canalis palatinus major to the mucous membrane of the hard and soft palate.

r.r. ganglionares - sensitive branches to the pterygopalatine parasympathetic ganglion, which lies in the fossa of the same name.

Mandibular nerve (n. mandibularis) comes out of the skull foramen ovale on the outer base of the skull and gives branches:

1. Motor - r.r. musculares innervate all masticatory muscles, m. mylohyoideus of the neck and venter anterior m. digastricus, as well as m. tensor veli palatini et m. tensoris tympani.

2. Sensitive:

N. buccalis - innervates the buccal mucosa.

N. lingualis - innervates the mucous membrane of the anterior 2/3 of the tongue to sulcus terminalis.

N. alveolaris inferior passes into the canal of the lower jaw, forms a plexus (plexus dentalis inferior), from which rami dentalis inferior exit to the teeth of the lower jaw and rami gingivalis inferior to the gums of the lower jaw, as well as the final branch - n. mentalis, which exits through the foramen mentale and innervates the skin of the lower lip and chin from the incision of the lips.

· N. auriculotemporalis accompanies a. temporalis superficialis and innervates the skin of the temporal region, auricle and external auditory canal.

VII pair - facial nerve (n. facialis). It has three cores:

1. Motor - n. motorius.

2. Sensitive - n. solitarius.

3. Parasympathetic - n. salivatorius superior.

The nuclei are embedded in the bridge. The nerve exits the brain between the pons and the medulla oblongata. The function of the nerve is mixed, as it has motor, sensory and parasympathetic fibers. Sensitive and parasympathetic fibers form n. intermedius, which comes with n. facialis. N. facialis and n. intermedius go into the canal of the facial nerve, exit the canal through the foramen stylomastoideum.

N. facialis gives off a branch in the canal - n. stapedius, which innervates m. stepedius.

N. intermedius gives off two branches in the canal:

N. petrosus major (parasympathetic in function) leaves the canal of the facial nerve through the hiatus canalis nervi petrosi majoris, passes in the sulcus of the same name, then through the foramen lacerum of the skull it enters the outer base of the skull, then through the canalis pterigoideus passes into the pterygopalatine fossa and ends in the pterygopalatine parasympathetic ganglia (ganglion pterygopalatinum). Postganglionic parasympathetic fibers emerge from the ganglion, some of which are part of n. zygomaticus (branch n. maxillaris) into the orbit through the lower orbital fissure and innervates the lacrimal gland. The second part of the fibers - n.n. nasales posteriores through the foramen sphenopalatinum go into the nasal cavity and innervate the glands of the nasal mucosa. Third part n.n. palatini through canalis palatinus major go into the oral cavity and innervate the mucous glands of the hard, soft palate, cheeks.

Chorda tympani - drum string contains sensory and parasympathetic fibers. Chorda tympani leaves the skull through the fissura petrotympanica, sensory fibers innervate the taste buds of the anterior 2/3 of the tongue. Parasympathetic fibers go to the submandibular parasympathetic ganglion (ganglion submandibulare), which are located on the diaphragm of the mouth, end in it, postganglionic fibers go as part of n. lingualis (a branch of n. mandibularis from n. trigeminus) to the sublingual and submandibular salivary glands.

After leaving the channel n. facialis gives only muscular branches:

N. auricularis posterior - innervates m. auricularis posterior et venter occipitalis m. epicranius.

· Ramus digastricus innervates the posterior abdomen m. digastricus and m. stylohioides.

Branches to mimic muscles: rami temporalis; r. zygomatici; r. buccales; r. marginalis mandibulae (marginal mandibular); r. colli innervates m. neck platysma.

Sensitive part n. intermedius has a ganglion of the knee (ganglion geniculi) in the canal. N. intermedius form parasympathetic fibers that emerge from the parasympathetic nucleus and peripheral processes of ganglion geniculi cells. The central processes of this ganglion are connected to the sensory nucleus.

The person has 12 pairs of cranial nerves(see diagrams below). Scheme of localization of the nuclei of cranial nerves: anteroposterior (a) and lateral (b) projections
The red color indicates the nuclei of the motor nerves, blue - sensitive, green - the nuclei of the vestibulocochlear nerve

Olfactory, visual, vestibulocochlear - nerves of highly organized specific sensitivity, which in their morphological features represent, as it were, peripheral parts of the central nervous system.

The article below will list all 12 pairs of cranial nerves, information about which will be accompanied by tables, diagrams and figures.

For more convenient navigation through the article, there is a picture with clickable links above: just click on the name of the pair of CNs you are interested in and you will immediately be transferred to information about it.

12 pairs of cranial nerves

1 pair of cranial nerves - olfactory (nn. olfactorii)

2 pair of cranial nerves - visual (n. opticus)

With damage to the 2nd pair of cranial nerves, various types of visual impairment can be observed, shown in the figure below.

Any pathology from optic nerve requires a mandatory check of the fundus, the possible results of which are shown in the figure below.

Fundus examination

3 pair of cranial nerves - oculomotor (n. oculomotorius)

Innervation of the muscles of the eye

3rd pair of cranial nerves is involved in the innervation of the muscles involved in the movement of the eye.

- it's complicated reflex act, in which not only 3 pairs are involved, but also 2 pairs of cranial nerves. The diagram of this reflex is shown in the figure above.

4 pair of cranial nerves - block (n. trochlearis)

5 pair of cranial nerves - trigeminal (n. trigeminus)

The dendrites of sensitive cells form three nerves along their course (see the innervation zones in the figure below):

• orbital- (zone 1 in the figure),
• maxillary- (zone 2 in the figure),
• mandibular- (zone 3 in the figure).

From skull n. ophthalmicus exits through fissura orbitalis superior, n. maxillaris - through foramen rotundum, n. mandibularis - through the foramen ovale. As part of one of the branches n. mandibularis, which is called n. lingualis, and chorda tympani taste fibers are suitable for the sublingual and mandibular glands.

When involved in the process of the trigeminal node, all types of sensitivity suffer. This is usually accompanied by excruciating pain and the appearance of herpes zoster on the face.

When involved in the pathological process of the nucleus n. trigeminus, located in the spinal tract, the clinic is accompanied by dissociated anesthesia or hypesthesia. At partial lesion segmental annular zones of anesthesia are noted, known in medicine under the name of the scientist who discovered them " Zelder zones" (see diagram). When the upper parts of the nucleus are affected, the sensitivity around the mouth and nose is disturbed; lower - outer parts of the face. Processes in the nucleus are usually not accompanied by pain.

6 pair of cranial nerves - abducens (n. abducens)

Abducens nerve (n. abducens) - motor. The nerve nucleus is located in the inferior part of the pons, under the floor of the fourth ventricle, lateral and dorsal to the dorsal longitudinal bundle.

Damage to the 3rd, 4th, and 6th pairs of cranial nerves causes total ophthalmoplegia. With paralysis of all the muscles of the eye, there is external ophthalmoplegia.

The defeat of the above pairs, as a rule, is peripheral.

Eye innervation

Without the friendly functioning of several components of the muscular apparatus of the eye, it would be impossible to carry out the movements of the eyeballs. The main formation, thanks to which the eye can move, is the dorsal longitudinal fasciculus longitudinalis, which is a system that connects the 3rd, 4th and 6th cranial nerves with each other and with other analyzers. Cells of the nucleus of the dorsal longitudinal bundle (Darkshevich) are located in the cerebral peduncles laterally from the cerebral aqueduct, on the dorsal surface in the region of the posterior commissure of the brain and frenulum. The fibers go down along the aqueduct of the large brain to the rhomboid fossa and on their way approach the cells of the nuclei of 3, 4 and 6 pairs, making a connection between them and a coordinated function. eye muscles. The composition of the dorsal bundle includes fibers from the cells of the vestibular nucleus (Deiters), which form ascending and descending paths. The first ones contact with the cells of the nuclei of the 3rd, 4th and 6th pairs, the descending branches stretch down, pass in the composition, which end at the cells of the anterior horns, forming tractus vestibulospinalis. The cortical center, which regulates voluntary gaze movements, is located in the region of the middle frontal gyrus. The exact course of the conductors from the cortex is unknown; apparently, they go to the opposite side to the nuclei of the dorsal longitudinal bundle, then along the dorsal bundle to the nuclei of these nerves.

Through the vestibular nuclei, the dorsal longitudinal bundle is connected with vestibular apparatus and the cerebellum, as well as with the extrapyramidal part of the nervous system, through the tractus vestibulospinalis - with the spinal cord.

7 pair of cranial nerves - facial (n. facialis)

The scheme of the topography of the facial nerve is presented above.

Intermediate nerve (n. intermedius)

The intermediate nerve is essentially part of the facial.

With damage to the facial nerve, or rather its motor roots, there is paralysis of the mimic muscles of the peripheral type. The central type of paralysis is a rare phenomenon and is observed when the pathological focus is localized in, in particular, in the precentral gyrus. The differences between the two types of mimic muscle paralysis are shown in the figure above.

8 pair of cranial nerves - vestibulocochlear (n. vestibulocochlearis)

The vestibulocochlear nerve anatomically has two roots with completely different functional abilities(this is reflected in the title of the 8th pair):

1. pars cochlearis, performing the auditory function;
2. pars vestibularis, which performs the function of a static feeling.

Pars cochlearis

Other names for the root: "lower cochlear" or "cochlear part".