What Is a Medial Nerve?

The inner bulge, each side is divided into two parts, the inner and the outer part by the vertical ditch: the inner part is located between the median ditch and the ditch, which is called the inner bulge. On the medial bulge, two small triangular areas can be seen below the medullary stratum: the hypoglossal nerve triangle and the sublingual nerve nucleus are located on the inner side;

Chinese name: Medial bulge
Each side: The vertical ditch is divided into two parts, the inside and the outside.

Inside: Located between the middle ditch and the boundary ditch
Small triangle: Hypoglossal nerve triangle

Medial bulge anatomy:

1 Medial bulge 1. Fourth ventricle:

The fourth ventricle is a gap between the medulla oblongata, the pons and the cerebellum. It is connected to the middle cerebral aqueduct to the third ventricle and to the central tube of the spinal cord. The bottom is a diamond-shaped nest with the top of the chamber facing the cerebellum, which looks like a tent. The ventricle expands to both sides to form the fourth ventricular lateral recess, and the distal opening of the ventricle forms a lateral hole leading to the subarachnoid space.

The fourth ventricle communicates with the subarachnoid space through the three holes on its top. The lateral foramen are located at the cerebellar angle of the pontine, the inner side is the rope body, and the outer side is the cerebellum. The hole near the lower corner of the diamond-shaped fossa is the median hole, and its lower boundary is the latch. The cerebrospinal fluid in the ventricle of the brain can directly enter the subarachnoid space through these three holes.

The bottom of the fourth ventricle is diamond-shaped and can be divided into upper, middle and lower parts. The upper part is triangular, pointed upward, leading to the midbrain aqueduct; the middle part is wide, reaching outward to the lateral recess; the lower part is also triangular, pointed downward, and leads to the closed central tube. The transverse fiber bundles on the middle surface are called pith, which define the boundary between the pontine and the medulla.

The superficial depression above the medullary pattern is called the upper depression, and the inner circular bulge is called the facial mound. The deep part of the facial nerve bypasses the abductor nucleus. The medial bulge is connected below the face mound, and the outer edge of the medial bulge is the boundary groove, which is the boundary between the motor nucleus of the trigeminal nerve and the lateral sensory nucleus.

The triangular plate formed at the lower end of the diamond-shaped fossa (inferior corner of the fourth ventricle) is called a latch, and the dynamic changes of the cerebrospinal fluid of the latch are closely related to the formation of cervical cavity.

2 Medial bulge 2. Hypoglossal nerve triangle:

In the lower part of the rhomboid fossa of the fourth ventricle, there is a triangular area called the hypoglossal nerve triangle. This triangle contains the hypoglossal nucleus. A hypoglossal nerve emanates from this nucleus.

3 Medial bulge 3. Dorsal nucleus of vagus nerve:

The dorsal nucleus of the vagus nerve is a parasympathetic nucleus in the medulla oblongata. Located on the deep side of the rhombic fossa vagus triangle, outside the hypoglossal nucleus. Visceral motor fibers emitted by the nucleus constitute the main component of the vagus nerve.

4 Inner bulge 4, boundary ditch:

On the back of the tongue, there is a V-shaped structure that opens forward. The tongue is divided into a tongue body and a tongue base with the boundary groove as a boundary. In front of the boundary ditch, there are 7 to 11 contour nipples, which contain taste buds, so they have a taste function.

5 Medial bulge 5, diamond-shaped nest:

It consists of the pontine and the dorsal surface of the medulla oblongata, forming the fourth ventricle floor. The upper side of the fossa is the joint arm, and the lower sides are bounded by ropes, wedge bundle nodules, and thin bundle nodules. The fossa floor is covered with a thin layer of gray matter, which is continuous with the central gray matter of the central duct and midbrain water duct. The lateral corners are quite lateral crypts. Between the upper and lower corners, there is a longitudinal middle groove, and the boundary grooves parallel to it on both sides divide the bottom of the fossa into the inner motion area and the outer sensory area. In the middle of the fossa, there are several transverse fiber bundles located in the gray matter below the ventricular membrane, called the pith. The medullary pattern divides the fossa into upper, middle and lower parts: the upper and lower parts are triangular. In the upper part of the fossa, there is a vertical bulge between the boundary sulcus and the median sulcus, which is called the medial bulge. The deep part has a structure such as the medial longitudinal bundle. There is a pair of circular bulges near the medullary stratum, that is, the facial nerve mound Spreading the nucleus). In the outer region at the upper end of the boundary groove, blue spots can be seen, called blue spots, which contain pigmented nerve cell clusters. The boundary groove is particularly obvious in the upper and lower parts of the medullary pattern, and it is concave, which is called as concave and concave. In the lower part of the fossa, between the boundary ditch and the median sulcus, there are two shallow ditches inward and downward, which are divided into three small triangular areas: the upper and lower sides are called the hypoglossal nerve triangles, and the hypoglossal nerve nucleus is deep in it; The middle is called the gray wing or the vagus nerve triangle, and the deep part has the dorsal nucleus of the vagus nerve. The lower lateral triangle is approximately band-shaped and is called the final zone, which is rich in blood vessels and glial. The large triangular area (including the upper and lower part of the medullary striae) outside the entire sulcus is collectively referred to as the vestibular area, with the vestibular nucleus deep. There is a small nodule in the lateral corner of the vestibular region, called the auditory nodule, with a snail nucleus deep.