HYPOGLOSSAL NERVE [nervus hypoglossus (PNA, JNA, BNA); synonym par duodecimum nn. encephali] — XII couple craniocereberal (cranial, T.) nerves, innervates muscles of language and a firm cover of a brain.
Zh. Vinslou was for the first time called by a hypoglossal nerve in 1733. L. Heister called it n. motorius linguae.
The item of N originates from cells of a kernel of P. of N (nucleus n. hypoglossi) in a myelencephalon from where goes towards the basis of a brain where appears between a pyramid and an olive 10 — 15 roots creating a trunk of a nerve. Leaves a head cavity of P. of N via the channel of a hypoglossal nerve (the hypoglossal channel, T.), in Krom it is surrounded with a venous ring. In the hypoglossal channel the nerve gives branches to a firm meninx. In a neck the nerve goes down between a vagus nerve and an internal jugular vein in the beginning, then bends around outside an internal carotid artery, being located between it and an internal jugular vein (fig). Here it dugoobrazno crosses with an outside carotid artery, approaches under a back abdomen of a biventral muscle (m. digastricus) and a shilopodjyazychny muscle (m. stylohyoideus), adjoining to a side surface of a hypoglossal and lingual muscle (m. hyoglossus).
Item of N preferential motive. In its trunk there are also sensitive nerve fibrils entering it as a part of connecting branches from cells of the lower node of a vagus nerve from a lingual nerve of the V pair of cranial nerves and front branches of cervical spinal nerves (cervical nerves, T.), and sympathetic fibers, vstulayushchy in P. of N as a part of a connecting branch of an upper cervical node of a sympathetic trunk. On a neck the upper root of a cervical loop (radix superior ansae cervicalis) containing fiber both the nerve and the fibers which entered it as a part of a connecting branch from the first cervical nerve departs from the middle of the arc-shaped bend of P. of N. This root goes down the general carotid artery and connects to the lower root (radix inferior) consisting of nerve fibrils of front branches of the II—III cervical nerves forming a cervical loop (ansa cervicalis), branches a cut innervate scapular and hypoglossal, grudinopodjyazychny, grudinoshchitovidny muscles (mm. omohyoideus, sternohyoideus, sternothyroideus). From P.'s arch of N distalny an upper root of a cervical loop separates shchitovidno - a hypoglossal branch (ramus thyrohyoi-deus) to the muscle of the same name.
Final branches of P. of N are lingual branches (rr. linguales) suitable to a lower surface language (see) and the innervating his muscles: top and bottom longitudinal (mm. longitudinales superior et inferior), cross (m. transversus linguae), vertical (m. verticalis linguae), genioglossal (m. genioglossus), hypoglossal and lingual (m. hyoglossus) and shiloyazychny (styloglossus).
P.'s kernel of N by means of korkovoyaderny fibers (fibrae cortico-nucleares) is connected with bark of the lower third of a pretsentralny crinkle of a frontal lobe of an opposite hemicerebrum. There are bonds between cells of a kernel of P. of N not only the, but also the opposite side that provides exact synergy in the various movements of muscles of language.
P.'s Defeat and. observe at inflammatory processes in the nerve, a brain trunk or on a lower surface of cerebral hemispheres, at injuries of a nerve, tumors of a mouth floor, trunk of a nerve — to a neurinoma (see) less often to a neurofibroma (see)
P. of N, stones of submaxillary gland (gyudnizhnechelyustny gland, T.) and other diseases. At hemilesion of a kernel of P. of N or his trunk the phenomena develop neuritis (see), followed by paresis of muscles on the same party of language (gemiglossoparezy) or their paralysis (gemiglossoplegiya).
In an initial stage of defeat reveal the easy shift of language in the healthy party. In the same party also the average furrow of language is curved, its root is raised on the struck party. The patient cannot concern a tip of language of a cheek, teeth, a corner of a mouth. At protrusion language deviates in the struck party, and at retraction is displaced in healthy again. The diseases noted in the first days quickly undergo speech disturbances because muscle fibers of both half of language intertwine. Pains in language and a headache can be observed that demonstrates
involvement in process of sensitive fibers P. of N. In the subsequent the expressed atrophy of the corresponding half of language develops. Its surface becomes uneven, wrinkled, the mucous membrane of language becomes thinner, amplifies its skladchatost. Function of language is broken slightly. In cases of damage of a nerve on the site after its exit from a skull (wound and various patol. processes in soft tissues of a neck and upper cervical vertebras) are at the same time noted disorders of function and upper cervical nerves owing to existence of an anastomosis between them and P. in N, napr, during the swallowing the deviation of a throat in the healthy party is observed.
At defeat of a kernel of P. of N that often meets at amyotrophic side sclerosis (see), syringobulbias (see. Myelosyringosis ), disturbance of blood circulation in a brain trunk and other diseases, can arise alternating syndromes (see), including Jackson's syndrome which is characterized by symptoms of defeat of P. of N on the party of the center of defeat and a hemiplegia or a hemiparesis of extremities on the opposite side. At the same time the atrophy and fibrillar twitchings of the affected muscles of a yaza ~ and paresis of a circular muscle of a mouth, are noted by the shown istonchennost and a skladchatost of lips, impossibility to make whistle. It is explained by the fact that the motive fibers to a circular muscle of a mouth going in structure facial nerve (see), begin from cells of a kernel of P. of N. At bilateral defeat of kernels of P. of N the full immovability of language can develop (glossoplegia). In these cases the speech becomes impossible (anarthria), chewing and advance of a food lump in a mouth is broken. These symptoms are observed at bulbar paralysis (see).
Defeat of the central neuron of P. of N, injuries, tumors, inflammatory diseases, disturbances of blood circulation in a brain can be the reasons to-rogo, is followed by a gemiglossoplegiya or gemiglossoparezy the central genesis, for to-rykh lack of atrophies of the struck half of language and increase in a tone of the affected muscles are characteristic. At protrusion language deviates aside, opposite to the center of defeat. At the same time usually along with damage of muscles of language on the same party there is a spastic hemiparesis or hemiplegia (see).
At bilateral defeats of a cortical and nuclear way (the central neuron) the glossoplegia enters a symptom complex of a pseudobulbar syndrome (see. Pseudobulbar paralysis ). Language at such patients is intense even at rest and will tighten to a throat. At glossopareza of the central genesis of the patient can put out tongue, but the volume of this movement, as well as other differentiated movements of language, are limited. In case of damage of a cerebral cortex in nizhnetemenny and zadnelobny areas of a dominant hemisphere there can be a special type of apraxia of organs of articulation, at a cut note difficulties of the motor speech.
P.'s defeat N can be shown by myotonia of language (glossospasm) and hyperkinesias of language. The glossospasm quite often arises owing to inflammatory process in an oral cavity; it can be one of manifestations neuralgia (see) lingual a nerve it is also sometimes observed at a chorea, epilepsy, hysteria and other diseases. As a rule, at a glossospasm both half of language strain equally. The half glossospasm (gemiglossospazm) is characteristic of neurosises, in particular of hysteria. Hyperkinesias of language can be one of forms tic (see).
For identification of defeats of P. of N examine an oral cavity, define situation and volume of movements of language, character of its surface, a tone of muscles, existence or lack of a muscular atrophy, fibrillar twitchings, ability to make the chewing and deglutitory movements, investigate electroexcitability of muscles of language, conduct also their elektromiografichesky research (see. Electromyography ), check the speech.
Treatment of defeats of a hypoglossal nerve usually symptomatic; it is a part of complex treatment of a basic disease. At tumors and P.'s injuries of N carry out operational treatment.
Bibliography: Vinarsky E. H. Clinical displays of the central paresis of a hypoglossal nerve, Zhurn, neuropath. and psikhiat., t. 67, No. 3, page 347, 1967; Korsakova V. I. Features of functions and a microstructure of a hypoglossal nerve, in book: Adaptation of the person and animals is normal also of pathology, under the editorship of S. S. Poltyrev, page 172, Yaroslavl, 1973; M. B. and Fedorov E. A. Crawl. Main neuropathological syndromes, page 154, M., 1966; Larina V. N. A kernel of a hypoglossal nerve at the person, Arkh. annate., gistol, and embriol., t. 49, century 11, page 77, 1965; Acute management in neurostomatology, under the editorship of V. E. Grechko, page 7, M., 1981; Sinelnikov R. D. Atlas of anthropotomy, t. 2, page 44, etc., M., 1974; A. V Triumphs. Topical diagnosis of diseases of a nervous system, JI., '1974; In about d and 1 A. The cranial nerves, anatomy and anatomicoclinical correlations, Oxford, 1965.
Century of E. Grechko; P.F. Stepanov (An.).