Medial to the internal capsule is the caudate nucleus. The caudate nucleus is a large C-shaped structure divided into a head, body, and tail, which closely follows the shape of the lateral ventricle (eFig. 9.58). Rostrally, the head of the caudate has a large rounded shape that contributes to the lateral wall of the anterior horn of the lateral ventricle (eFig. 9.58). Also at this level, the head of the caudate is continuous with the putamen (eFig. 9.59). Because of this close relationship the putamen and caudate are referred to collectively as the striatum. At the level of the interventricular foramen, the head of the caudate transitions to the body. The body of the caudate is long and narrows substantially as it transitions from the head to the tail (eFig. 9.59). Along its course the body contributes to the floor of the lateral ventricle. Near the posterior border of the thalamus the body of the caudate transitions into the tail. The tail continues anteriorly within the roof of the inferior horn of the lateral ventricle to terminate in the amygdaloid nucleus (eFig. 9.59).