Hypoglossal nerve

Hypoglossal nerve (nervus hypoglossus) - twelfth steam of cranial nerves. Is a motor nerve innervates the muscles of the tongue (Fig). Start taking cells from the kernel P. N. in the medulla, the lower of which is located in front of the Central channel, and top - to-bottom of the fourth ventricle, under the triangle P. N. (trigonum n. hypoglossi). The length of the kernel about 2 refer To the kernel hypoglossal nerve suitable fiber from the bark of the lower divisions precentral.net region (tractus corticonuclearis), from sensitive engine of the trigeminal nerve. It's over fiber, linking it with nuclei wandering, language-pharyngeal and facial nerves. The core of P. N. divided into three parts - the front, rear-internal and rear-outer. It consists of a large cells, about which ends in a large number of fibers owned actually fibers P. N. These fibers connect parts of the kernel that party where they are located, and the opposite. Departing from the cell nucleus hypoglossal nerve fibers penetrate the thickness of the medulla oblongata and go on its front surface, in the Antero-lateral sulcus between pyramidonum and Oliva. P. N. leaves a cavity of a skull through sublingual channel (canalis hypoglossi), passing first through the foramen hipoglossi in the occipital bone. On leaving the skull goes backwards and inwards from the vagus nerve, internal jugular vein and carotid artery; going down to the bottom, forming a loop (ansa cervicalis) and gives the end twigs, Innervate the muscles of the tongue. P. N. has anastomoses with upper cervical node, with the top node of the vagus nerve that branches of the trigeminal nerve and with other entities. A small part of fibers P. N. associated with the vagus nerve, has a touch of nature. P. N. ensures the movements of different groups of muscles of tongue, guides its movement in different directions. The muscles of the tongue in isolation is not reduced. This synergy of muscles of tongue is explained by the variety of relationships between cores P. N.

topography hypoglossal nerve
Topography hypoglossal nerve: 1 - n. hypoglossus; 2 - n. lingualis; 3 - n. glosso-pharyngeus; 4 - chorda tympani; 5 - n. facialis.

The defeat of the hypoglossal nerve is seldom isolated, often together with other cranial nerves. Unilaterally to defeat P. N. there is clearly expressed deviation language at the protrusion the affected side, degenerative atrophy corresponding half and fibrillar jerking it. It basically does not suffer. Supranuclear paralysis P. N. different from the peripheral to the fact that almost always accompanies hemiplegia. When bilateral supranuclear defeat paralysis hypoglossal nerve is one of the symptoms of pseudobulbar palsy and is accompanied by a violation of the functions of the vagus nerve. It suffer and reminds bulbar (impaired articulation, nasal tone, aphonia). Treatment of diseases of P. N. symptomatic.