Each olivary body is located on the anterior surface of the medulla lateral to the
pyramid, from which it is separated by the
antero-lateral sulcus and the fibers of the
hypoglossal nerve. Behind (
dorsally), it is separated from the
postero-lateral sulcus by the
ventral spinocerebellar fasciculus. In the depression between the upper end of the olive and the
pons lies the
vestibulocochlear nerve. In humans, it measures about 1.25 cm in length, and between its upper end and the pons there is a slight depression to which the roots of the
facial nerve are attached. The external arcuate fibers wind across the lower part of the pyramid and olive and enter the inferior peduncle.
Olivary nuclei The olive consists of two parts: • The
inferior olivary nucleus (or 'complex'), which is a part of the
olivo-cerebellar system and is mainly involved in cerebellar motor-learning and function. • The
superior olivary nucleus, considered part of the
pons and part of the
auditory system, aiding the perception of
sound. The inferior olive in itself is divided to 3 main nuclei: • The
primary olivary nucleus (PO) which consist of the major laminar structure. • The
medial accessory olivary nucleus (MAO) lies between the primary olivary nucleus and the pyramid, and forms a curved
lamina, the concavity of which is directed laterally. • The
dorsal accessory olivary nucleus (DAO) is the smallest, and appears on transverse section as a curved lamina behind the primary olivary nucleus. Small additional inferior olivary structures consist of the dorsal cap of Kooy and the ventrolateral outgrowth. ==Additional images==