On the right side the superficial gray matter and medullary white substance of the parahippocampal gyrus have been cleaned away to expose cortical substance on the deep aspect of the gyrus. Fine digitations are characteristic of this deep cortical substance. The cut edge of the alveus can also be seen. Note the hook or uncus of the parahippocampal gyrus. On the smooth inferior surface of the uncus is the delicate, transversely running tail of the dentate gyrus that runs into the cleft of the uncus.
More anterior is the amygdaloid body.
Note the characteristic, toothlike appearance of the inferior surface of the dentate gyrus. Anteriorly, the dentate gyrus abruptly turns, medially and posteriorly, thereby forming the tail of the dentate gyrus. Two gray elevations located anterior and anteromedial to the tail of the dentate gyrus are parts of the deep cortex of the uncus. Note the broad white sheet of the alveus and, just medial to the dentate gyrus, the fimbria of the hippocampus, a thick white bundle of axons that runs first backwards, then forwards and superiorly to form the highly arched crus of the fornix. Between the two crura of the fornix is a white, triangular lamina, known as the fornical commissure.