At the junction of the floor and anterior wall of the third ventricle, immediately above the optic chiasma, the ventricle presents a small angular recess or diverticulum, the optic recess (or supraoptic recess).

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  Drawing of a cast of the ventricular cavities, viewed from the side.

This article incorporates text in the public domain from page 816 of the 20th edition of Gray's Anatomy (1918)