Olivary body

Brain: Olivary body
The medulla, showing the olivary bodies lying adjacent to the pyramids.
Transverse section of medulla oblongata below the middle of the olive.
Latin	oliva
Gray's	p.781
Part of	Medulla
MeSH	Olivary+Nucleus

In anatomy, the olivary bodies or simply olives (Latin oliva and olivae, singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. They contain the olivary nuclei.

External anatomy

The 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 separate parts:

• The inferior olivary nucleus or the inferior olivary complex, which is a part of the olivo-cerebellar system and is mainly involved in cerebellar motor-learning and function.

• The superior olivary nucleus is considered part of the pons and is a 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

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  Schematic representation of the chief ganglionic categories (I to V).

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  Superficial dissection of brain-stem. Lateral view.

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  Deep dissection of brain-stem. Lateral view.

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  Deep dissection of brain-stem. Lateral view.

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  Deep dissection of brain-stem. Ventral view.

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  Section of the medulla oblongata at about the middle of the olive.

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  Diagram showing the course of the arcuate fibers.

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  The formatio reticularis of the medulla oblongata, shown by a transverse section passing through the middle of the olive.

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  Dissection showing the projection fibers of the cerebellum.

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  Basal view of a human brain

External links

• Gray's s187 (primary source for article)
• Stained brain slice images which include the "Olivary%20nucleus" at the BrainMaps project

This article incorporates text from a public domain edition of Gray's Anatomy.