Basal (subcortical) nuclei
Last reviewed: 23.04.2024
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Basal (subcortical) nuclei and white matter of the terminal brain
In addition to the cortex that forms the surface layers of the terminal brain, the gray matter in each of the cerebral hemispheres lies in the form of separate nuclei, or nodes. These nodes are in the thickness of white matter, closer to the base of the brain. Accumulations of gray matter in connection with their position are called basal (subcortical, central) nuclei (nuclei basales), or nodes. The basal nuclei of the hemispheres include a streaky body consisting of caudate and lenticular nuclei, a fence and an amygdala.
The stripped body (corpus striatum) received its name due to the fact that on horizontal and frontal sections of the brain it has the appearance of alternating bands of gray and white matter. The caudate nucleus (nucleus caudatus) is most medial and in front. It is located anterior to the thalamus, from which (on a horizontal section) it is separated by a strip of white matter - the front leg of the inner capsule. The anterior part of the caudate nucleus is thickened and forms a caput, which forms the lateral wall of the anterior horn of the lateral ventricle. Located in the frontal lobe of the hemisphere, the head of the caudate nucleus adjoins the anterior perforated substance. At this point, the head of the caudate nucleus joins the lenticular nucleus. Tapering posteriorly, the head extends into a thinner body (corpus), which lies in the region of the bottom of the central part of the lateral ventricle and is separated from the thalamus by a terminal strip of white matter. The posterior part of the caudate nucleus - the tail (cauda) gradually becomes thinner, bends downward, participates in the formation of the upper wall of the lower horn of the lateral ventricle. The tail reaches the amygdala, which lies in the anterior medial divisions of the temporal lobe (behind the anterior perforated substance). Lateral to the head of the caudate nucleus is a layer of white matter - the anterior leg (thigh) of the inner capsule separating this nucleus from the lenticular.
Lentil nucleus (nucleus lentiformis), received its name for its similarity with lenticular grain, is lateral to the thalamus and caudate nucleus. From the thalamus, the lenticular nucleus is separated by the hind leg (thigh) of the inner capsule. The lower surface of the anterior section of the lenticular nucleus is attached to the anterior perforated substance and connects to the caudate nucleus. The medial part of the lenticular nucleus on the horizontal section of the brain narrows and turns toward the knee of the inner capsule, located on the border of the thalamus and the head of the caudate nucleus.
The lateral surface of the lenticular nucleus is convex and faces the base of the islet part of the cerebral hemisphere. On the frontal section of the brain, the lenticular nucleus has the shape of a triangle, the apex of which is turned into the medial, and the base - to the lateral side. Two parallel vertical interlayers of white matter, located almost in the sagittal plane, divide the checheviiobraznoe. The core into three parts. The most lateral is the shell (putamen), which has a darker color. The medial shell is two light medial plates - the medial and lateral (laminae medullares medialis et lateralis), which are united by the common name "pallid shor" (globus pallidus).
The medial plate is called the medial pallid sphere (globus pallidus medialis), the lateral one is called the lateral pallid globus (globus pallidus lateralis). The horsetail nucleus and the shell belong to the phylogenetically newer formations (neosti latum, S. Striatum). The pale sphere is an older formation (paleostriatum, s. Pallidum).
Fence (claustrum) is located in the white substance of the hemisphere, on the side of the shell, between the last and the cortex of the islet lobe. The fence has the appearance of a thin vertical plate of gray matter. From the shell it is separated by a layer of white matter - the outer capsule (capsula externa), from the bark of the islet - the same layer, called the "most external capsule" (capsula extria).
The almond-shaped body (corpus amygdaloideum) is found in the white matter of the temporal lobe of the hemisphere, approximately 1.5-2.0 cm posterior to the temporal pole.
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