The lentiform nucleus lies lateral to the internal capsule. Laterally, it is separated from the claustrum by fibres of the external capsule. (Note that these capsules are so called because they appear, by naked eye, to form a covering for the lentiform nucleus). Superiorly, the lentiform nucleus is related to the corona radiata, and inferiorly to the sublentiform part of the internal capsule. Some other relationships are evident in Fig. 13.2. The lentiform nucleus appears triangular (or wedge shaped) in coronal section. It is divided, by a thin lamina of white matter, into a lateral part, the putamen; and a medial part, the globus pallidus. The globus pallidus is further subdivided into medial and lateral (or internal and external) segments.
This is a thin lamina of grey matter that lies lateral to the lentiform nucleus. It is separated from the latter by fibres of the external capsule. Laterally, it is separated by a thin layer of white matter from the cortex of the insula. Its connections and functions are unknown.
This complex (also called the amygdaloid body, amygdala) lies in the temporal lobe of the cerebral hemisphere, close to the temporal pole. It lies deep to the uncus, and is related to the anterior end of the inferior horn of the lateral ventricle.