| Posterior commissure | |
|---|---|
 Sagittal cross-section of thehuman brain. Theposterior commissure is labelled at center top. | |
 The posterior commissure labelled on a human brain | |
| Details | |
| Part of | Human brain |
| Identifiers | |
| Latin | commissura posterior |
| MeSH | D066243 |
| NeuroNames | 484 |
| NeuroLex ID | birnlex_1026 |
| TA98 | A14.1.08.416 |
| TA2 | 5749 |
| FMA | 62072 |
| Anatomical terms of neuroanatomy | |
Theposterior commissure (also known as theepithalamic commissure) is a rounded band of white fibers crossing the middle line on the dorsal aspect of the rostral end of thecerebral aqueduct. It is important in the bilateralpupillary light reflex.[citation needed] It constitutes part of theepithalamus.[1]
Its fibers acquire their medullary sheaths early, but their connections have not been definitively determined. Most of them have their origin in a nucleus, thenucleus of the posterior commissure (nucleus of Darkschewitsch), which lies in theperiaqueductal grey at rostral end of the cerebral aqueduct, in front of theoculomotor nucleus. Some are thought to be derived from the posterior part of thethalamus and from thesuperior colliculus, whereas others are believed to be continued downward into themedial longitudinal fasciculus.
For the pupillary light reflex, theolivary pretectal nucleus innervates bothEdinger-Westphal nuclei. To reach the contralateral Edinger-Westphal nucleus, the axons cross in the posterior commissure.
This article incorporates text in thepublic domain frompage 812 of the 20th edition ofGray's Anatomy(1918)
