Go Cranial nerves vagusous accessory hypoglossal

Cranial nerves

X pair, the vagus nerve (n. Vagus), is very widespread and forks mainly in the internal organs. Its trunk originates 10 - 15 roots in the field of an oblong brain, behind the IX couple. The common trunk of the X pair exits the skull through the jugular aperture together with the IX and XI pairs of cranial nerves. The sensory fibers of the vagus nerve start from the upper and lower nodes lying near the jugular opening. Upon exiting the skull X, the pair goes down, passes in the neck and penetrates into the chest and abdominal cavity. The left vagus nerve enters the chest cavity between the left carotid and subclavian arteries and, falling down the anterior surface of the esophagus, forks on the anterior surface of the stomach. The right vagus nerve, entering the chest cavity, lies between the right subclavian artery and vein. From him leaves the recurrent nerve (n. Laryngeus recurrens). The right vagus nerve is part of the celiac plexus. The sensory fibers of the X pair innervate the mucous membrane of the pharynx, larynx, root of the tongue and, together with the V and IX pairs of the cranial nerves, the dura mater. They end in the core of a single bundle and in other nuclei of the posterior part of the rhomboid fossa. The fibers innervating the internal organs of the thoracic and abdominal cavities originate in the dorsal nucleus X of the pair of cranial nerves. Motor fibers X pairs of cranial nerves depart from the double core of the tire. The motor nuclei of the vagus nerve are connected with the cerebral cortex through the fibers in the pyramidal bundle. Parasympathetic fibers that form part of the vagus nerve also innervate the organs of the thoracic and abdominal cavities.


With the defeat of the vagus nerve, paresis of the soft palate , larynx, pharynx occurs and symptoms of disturbed activity of the internal organs are identified. In bilateral lesions, a disorder of swallowing, food ingestion in the nose, nasal hue of speech, and sometimes pain in the auricle are noted. When the vagus nerve is damaged at the level of retreat from the recurrent nerve, aphonia and breathing difficulties occur. The defeat of the heart branches causes tachycardia , their irritation - bradycardia. Sometimes there are heart crises with sharp pains. With a unilateral lesion of the vagus nerve - the palatine curtain is lowered on the side of the lesion, the tongue is deflected to a healthy side. Bilateral lesions of the vagus nerve always have a difficult prognosis.

The XI pair, the accessory nerve (n. Accessorius), begins in two parts: the upper, extending from the posterior part of the double nucleus lying in the medulla, and the lower, coming from the spinal nucleus, located in the anterior horns of the upper segments of the spinal cord . The roots of the lower part enter the skull through the large occipital foramen and join the upper part of the nerve. The roots of the upper part go behind the olive, located behind the roots of the X pair. From the cavity of the skull, the accessory nerve comes out with the X pair and is divided into two branches - the outer and the inner. Part of the XI fiber pair of cranial nerves becomes part of the vagus nerve. The accessory nerve innervates the trapezius and sternocleidomastoid muscles. With his defeat and paralysis or paresis of these muscles. Occurs constriction of the palpebral fissure, enophthalmos (retraction of the eyeball), miosis (constriction of the pupil) as a result of simultaneous involvement of the upper cervical node in the process.

XII pair, hypoglossal nerve (n. Hypoglossus). The nucleus of this nerve is located in the lower part of the rhomboid fossa. His numerous roots go between the pyramid and olive. Then, coming out of the cranial cavity, they pass through the canal of the hypoglossal nerve, downwards from the hyoid bone, then they are divided into terminal branches that innervate the muscles of the tongue.

With the defeat of this nerve, limitation of movements of the tongue forward and its deviation to the diseased side, muscle atrophy, fibrillary twitching, pain in the root of the tongue are found.