The olivary bodies or simply olives (Latin ''oliva'' and ''olivae'', singular and plural, respectively) are a pair of prominent oval structures on either side of the

medullary pyramid In neuroanatomy, the medullary pyramids are paired white matter structures of the brainstem's medulla oblongata that contain motor fibers of the corticospinal and corticobulbar tracts – known together as the pyramidal tracts. The lower limit ...

s in the medulla, the lower portion of the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

. They contain the olivary nuclei.

Structure

Each olivary body is located on the anterior surface of the medulla lateral to the

pyramid A pyramid () is a structure whose visible surfaces are triangular in broad outline and converge toward the top, making the appearance roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as trian ...

, from which it is separated by the antero-lateral sulcus and the fibers of the

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated b ...

. Behind (

dorsally Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

), it is separated from the

postero-lateral sulcus The accessory, vagus, and glossopharyngeal nerve The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongat ...

by the

ventral spinocerebellar fasciculus The spinocerebellar tracts are nerve tracts originating in the spinal cord and terminating in the same side (ipsilateral) of the cerebellum. The two main tracts are the dorsal spinocerebellar tract, and the ventral spinocerebellar tract. Both of ...

. In the depression between the upper end of the olive and the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of ...

lies the

vestibulocochlear nerve The vestibulocochlear nerve or auditory vestibular nerve, also known as the eighth cranial nerve, cranial nerve VIII, or simply CN VIII, is a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the br ...

. 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 The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

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 The inferior olivary nucleus (ION) is a structure found in the medulla oblongata underneath the superior olivary nucleus.Gado, Thomas A. Woolsey; Joseph Hanaway; Mokhtar H. (2003). The brain atlas a visual guide to the human central nervous syste ...

(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 The superior olivary complex (SOC) or superior olive is a collection of brainstem nuclei that is located in pons, functions in multiple aspects of hearing and is an important component of the ascending and descending auditory pathways of the aud ...

, considered part of the

and part of the

auditory system The auditory system is the sensory system for the sense of hearing. It includes both the ear, sensory organs (the ears) and the auditory parts of the sensory system. System overview The outer ear funnels sound vibrations to the eardrum, incre ...

, aiding the perception of

sound In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the br ...

. 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 Lamina may refer to: People * Saa Emerson Lamina, Sierra Leonean politician * Tamba Lamina, Sierra Leonean politician and diplomat Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathem ...

, 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

File:Gray679.png, The medulla, showing the olivary bodies lying adjacent to the pyramids. File:Gray695.png, Transverse section of

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

below the middle of the olive. File:Gray690.png, Deep dissection of brain-stem. Ventral view. File:Gray699.png, Diagram showing the course of the arcuate fibers. File:Gehirn, basal - beschriftet lat.svg, Basal view of a human brain

References

External links

* Medulla oblongata {{Portal bar, Anatomy