The lentiform nucleus or lenticular nucleus comprises the putamen and the globus pallidus within the basal ganglia. With the caudate nucleus it forms the striatum. It is a large, lens-shaped mass of gray matter just lateral to the internal capsule.
Schematic representation of the chief ganglionic categories (I to V).
|Anatomical terms of neuroanatomy|
When divided horizontally, it exhibits, to some extent, the appearance of a biconvex lens, while a coronal section of its central part presents a somewhat triangular outline.
It is shorter than the caudate nucleus and does not extend as far forward.
It is lateral to the caudate nucleus and thalamus, and is seen only in sections of the hemisphere.
Its anterior end is continuous with the lower part of the head of the caudate nucleus and with the anterior perforated substance.
In a coronal section through the middle of the lentiform nucleus, two medullary laminae are seen dividing it into three parts.
The lateral and largest part is of a reddish color, and is known as the putamen, while the medial and intermediate are of a yellowish tint, and together constitute the globus pallidus; all three are marked by fine radiating white fibers, which are most distinct in the putamen.