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 pyramids 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.
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
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 (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
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, 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 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