|Brain: Habenular commissure|
The habenular commissure, is a brain commissure (a band of nerve fibers) situated in front of the pineal gland that connects the habenular nucleus on one side of the diencephalon with that on the other side.
The habernular commissure is part of the trigonum habenulæ (a small depressed triangular area situated in front of the superior colliculus and on the lateral aspect of the posterior part of the tænia thalami). The trigonum habenulæ also contains groups of nerve cells termed the ganglion habenulæ. Fibers enter the trigonum habenulæ from the stalk of the pineal gland, and the habenular commissure. Most of the trigonum habenulæ's fibers are, however, directed downward and form a bundle, the fasciculus retroflexus of Meynert, which passes medial to the red nucleus, and, after decussating with the corresponding fasciculus of the opposite side, ends in the interpeduncular ganglion.
Nerve cell fibers enter the trigonum habenulæ from the stalk of the pineal body, and the habernular commissure.