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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.
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.
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
a site of union of corresponding parts, as the angle of the lips or eyelids; used also with specific reference to the sites of junction between adjacent cusps of the heart valves.
the bands of fibers connecting the parts of the two cerebral hemispheres. They include the corpus callosum, the largest commissure, a rostral commissure which is part of the paleopallium and the fornical commissure which is related to the archipallium, the caudal collicular commissure which connects the caudal colliculi (corpora quadrigemina). Called also cerebral commissure.
see brain commissure (above).
interconnection between the right and left hippocampi. Called also fornical commissure.
interconnection between the right and left habenular nuclei.
a band of gray matter joining the optic thalami; it develops as a secondary adhesion and may be absent.
a large fiber bundle crossing from one side of the cerebrum to the other dorsal to where the aqueduct opens into the third ventricle.
spinal cord commissure
the gray and white commissures which connect the two sides of the spinal cord.