Olivary body

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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.

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, 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.

The olivary nuclei consist of the following nuclei:

• The inferior olivary nucleus.

• The medial accessory olivary nucleus lies between the inferior olivary nucleus and the pyramid, and forms a curved lamina, the concavity of which is directed laterally. The fibers of the hypoglossal nerve, as they traverse the medulla, pass between the medial accessory and the inferior olivary nuclei.

• The dorsal accessory olivary nucleus is the smallest, and appears on transverse section as a curved lamina behind the inferior olivary nucleus.

• The superior olivary nucleus is considered part of the pons.

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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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