posterior commissure

Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to posterior commissure: fornix, pretectal nucleus, commissura posterior


1. a site of union of corresponding parts, such as the angle of the lips or eyelids.
2. the site of junction between adjacent cusps of a cardiac valve.
anterior commissure the band of fibers connecting the parts of the two cerebral hemispheres.
commissure of epithalamus a large fiber bundle that crosses the midline of the epithalamus just dorsal to the point where the cerebral aqueduct opens into the third ventricle.
middle commissure a band of gray matter joining the optic thalami; it develops as a secondary adhesion and may be absent.
posterior commissure commissure of epithalamus.

com·mis·sur·a pos·te·ri·or

a thin band of white matter, crossing from side to side beneath the habenula of the pineal body and over the aditus ad aqueductum cerebri; it is largely composed of fibers interconnecting the left and right pretectal region and related cell groups of the midbrain; it marks the junction of the diencephalon and mesencephalon.

posterior commissure

An axon tract running transversely through the gray matter that forms the roof of the cerebral aqueduct in the midbrain. This tract contains commissural axons interconnecting the right and left pretectal areas; it also contains decussating axons from each pretectal area to the contralateral Edinger-Westphal nucleus.
See also: commissure
References in periodicals archive ?
MUC6 and 7 were not expressed in any of the tested (vocal folds, laryngeal ventricles and posterior commissure) samples.
Posterior Commissure. MUC1 and 2 were expressed in LPR posterior commissure mucosa whereas these 2 mucin genes were not expressed in control mucosa.
MUC5AC down regulation was still significant in respiratory mucosa of the combined laryngeal and ventricular mucosa (P < 0.05) while statistical significance was lost in respiratory mucosa of posterior commissure mucosa.
MUC2 was expressed only in control ventricular mucosa and was absent in posterior commissure and vocal fold mucosa whereas MUC5AC was moderately expressed in the three locations to various extents.
MUC5AC was significantly down regulated in LPR mucosa from the ventricular and posterior commissure mucosa not in the vocal fold mucosa.
Lesions of the posterior commissure in the dorsal midbrain also impair vertical gaze, due to the disruption of bilateral crossing pathways.
Points for antero-posterior length and height were best appreciated on the cross sectional slice, the anterior point marked on the lamina terminalis, the posterior point on the posterior commissure points used in reference for antero-posterior length.
Direct laryngoscopy revealed the presence of pseudosulcus vocalis, partial ventricular obliteration, and posterior commissure hypertrophy, findings that are consistent with a diagnosis of laryngopharyngeal reflux.
The third patient had more extensive posterior commissure and interaryrenoid scarring.
The pineal gland, also known as pineal body, is a medium and odd endocrine organ, which originates in the second month of intrauterine life (Macchi & Bruce, 2004) as a diencephalon roof evagination with a conical shape (Bertolucci & Foa, 2004), is aimed antero-posterior and rests on the path that separates the upper colliculus of the posterior wall of the third ventricle and is joined habenular and posterior commissures (Rouviere & Delmas, 1999).
It is evaluated by determining the axis between the anterior and posterior commissures as compared with the frontal plane, but it is relatively difficult to measure in a reproducible manner.

Medical browser ?
Full browser ?