anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

, 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 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 ...

, 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 ...

. They contain the olivary nuclei.

Structure

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

pyramid A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrila ...

, 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 by ...

. 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 The pons (from Latin , "bridge") is part of the brainstem that in humans and other bipeds 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 (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

and part of the

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

, 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 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: Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics * Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwe ...

, 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

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