Hypoglossal nucleus
Encyclopedia
The hypoglossal nucleus is a cranial nerve nucleus
, and it extends the length of the medulla
, and being a motor nucleus, is close to the midline. In the open medulla, it is visible as what is known as the hypoglossal trigone, a raised area (medial to the vagal trigone
) protruding slightly into the fourth ventricle
.
In the closed medulla, the gracile
and cuneate nuclei
lie posteriorly, which means the nucleus is not as close to the back of the medulla as in the open medulla. It is, however, still close to the midline.
Cranial nerve nucleus
A cranial nerve nucleus is a collection of neurons in the brain stem that is associated with one or more cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by...
, and it extends the length of the medulla
Medulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
, and being a motor nucleus, is close to the midline. In the open medulla, it is visible as what is known as the hypoglossal trigone, a raised area (medial to the vagal trigone
Vagal trigone
The cells of the dorsal nucleus 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...
) protruding slightly into the fourth ventricle
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 ventricle...
.
In the closed medulla, the gracile
Gracile nucleus
Located in the medulla oblongata, the gracile nucleus is one of the dorsal column nuclei that participate in the sensation of fine touch and proprioception of the lower body...
and cuneate nuclei
Cuneate nucleus
One of the dorsal column nuclei, the cuneate nucleus is a wedge-shaped nucleus in the closed part of the medulla oblongata. It contains cells that give rise to the cuneate tubercle, visible on the posterior aspect of the medulla...
lie posteriorly, which means the nucleus is not as close to the back of the medulla as in the open medulla. It is, however, still close to the midline.
External links
- NIF Search - Hypoglossal Nucleus via the Neuroscience Information FrameworkNeuroscience Information FrameworkThe Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/genomic resources.-Description:...