commissura

commissura /com·mis·su·ra/ (kom″ĭ-su´rah) pl. commissu´rae   [L.] commissure.

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commissure [kom´ĭ-shūr]

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.

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commissure, commissura

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.

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brain commissure

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.

cerebral commissure

see brain commissure (above).

fornical commissure

interconnection between the right and left hippocampi. Called also fornical commissure.

habenular commissure

interconnection between the right and left habenular nuclei.

middle commissure

a band of gray matter joining the optic thalami; it develops as a secondary adhesion and may be absent.

posterior commissure

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.