The hypoglossal nucleus is a
cranial nerve nucleus
A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more of the cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions ...
, found within the
medulla
Medulla or Medullary may refer to:
Science
* Medulla oblongata, a part of the brain stem
* Renal medulla, a part of the kidney
* Adrenal medulla, a part of the adrenal gland
* Medulla of ovary, a stroma in the center of the ovary
* Medulla of t ...
. Being a motor nucleus, it is close to the midline. In the
open medulla, it is visible as what is known as the ''
hypoglossal trigone
In the upper part of the medulla oblongata, the hypoglossal nucleus approaches the rhomboid fossa
The rhomboid fossa is a rhombus-shaped depression that is the anterior part of the fourth ventricle. Its anterior wall, formed by the back of the po ...
'', a raised area (medial to the
vagal trigone
The cells of the dorsal nucleus of vagus nerve are spindle-shaped, like those of the posterior column of the spinal cord, and the nucleus is usually considered as representing the base of the posterior column. It measures about 2 cm. in length ...
) protruding slightly into the
fourth ventricle
The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ve ...
.
The hypoglossal nucleus is located between the
dorsal motor nucleus of the vagus and the midline of the medulla. Axons from the hypoglossal nucleus pass anteriorly through the medulla forming the
hypoglossal nerve
The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated by ...
which exits between the
pyramid
A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilat ...
and
olive
The olive, botanical name ''Olea europaea'', meaning 'European olive' in Latin, is a species of small tree or shrub in the family Oleaceae, found traditionally in the Mediterranean Basin. When in shrub form, it is known as ''Olea europaea'' ...
in a groove called the
anterolateral sulcus.
See also
*
Hypoglossal nerve
The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated by ...
Additional images
File:Gray695.png, Transverse section of medulla oblongata below the middle of the olive.
File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral view.
File:Medulla_oblongata_-_posterior_-_very_low_mag.jpg, Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a mic ...
showing the hypoglossal nuclei in relation to their surrounding structures.
File:Medulla_oblongata_-_posterior_-_cn_xii_-_high_mag.jpg, Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a mic ...
showing the hypoglossal nucleus. H&E-LFB stain.
External links
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Cranial nerve nuclei
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