Pons

The Pons ( Latin for " bridge ") is a section of the brain. He is, together with the cerebellum, the metencephalon ( hindbrain ). On a brain the bridge already falls on a cursory inspection to be significantly raised transverse ridge between the mesencephalon ( midbrain ) and Myelencephalon ( hindbrain ) on. Together with mesencephalon and Myelencephalon it forms the brain stem.

Anatomy

We divide the bridge into a front portion, the base ( basilar pontine ), and a rear portion, the pontine tegmentum ( pontine tegmentum ). In animals, this according to their body orientation are below or above.

At the base two longitudinal beads are recognizable, in which both sides runs the pyramidal tract ( pyramidal tract ). In the central gutter ( sulcus basilar ) between these paths is an important tributary of the blood supply to the brain runs, the basilar artery. Behind the Pons is a smaller transverse ridge, the trapezoid body (trapezoid body ), which runs the auditory pathway and the cranial nerve VI to VIII occur where the surface. The visible cross section line connecting both halves ( raphe ) consists mainly of crossing nerve fibers.

On the side of the bridge enters the very strong fifth cranial nerve ( trigeminal nerve ) to the brain surface.

The upper end of the bridge dome forms the front part of the floor of the rhomboid fossa ( fossa rhomboidea ) and thus of the fourth ventricle. The connection to the cerebellum represents both sides of the middle cerebellar peduncles ago ( cerebellar peduncle medius ).

Function

The bridge is a way station for all nerve fibers between the front and underlying portions of the central nervous system. In addition to these fiber strands ( white matter ) are the bridge some collections of nerve cell bodies, the pontine nuclei ( nuclei pontis ). You are switching station of the connections between the cerebrum and cerebellum, crossing to the left in the area of ​​the bridge from left to right or right. On a cross-section of the bridge can be seen even with the naked eye, these cross-links ( Fibrae transversae pontis ).

In the pontine tegmentum are also a part of the reticular formation and motor nuclei of origin of certain cranial nerves (V, VI (nucleus nervi abducentis ), VII ).