Hypoglossal nucleus

The hypoglossal nucleus 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) protuding slightly into the fourth ventricle.

In the closed medulla, the gracial and cuneate nuclei lie posteriorly, which means the nucleus is less close to the back of the medulla (it is still close to the midline).