VAN 121: Veterinary Gross Anatomy-II (2+2)

HIPPOCAMPUS

• This is an invagination of the cerebral cortex at the lateral ventricle through the hippocampal sulcus. This gyrus curves from the deep face of the piriform lobe around the thalamus and forms the posterior part of the floor of the lateral ventricle.
• By careful blunt dissection along the posterior horn of the lateral ventricle into the piriform lobe, the hippocampus on each side can be easily separated and raised.
• On the ventral or deep face of the hippocampal gyrus a narrower band the dentate gyrus can be seen and laterally the two gyri separated by the hippocampal fissure.
• The dorsal or ventricular surface of the hippocampus is covered with white mater called the alveus derived from hippocampal and dentate gyri, which converge on the lateral margin to form a band of white mater called the fimbria which on either side continues forwards as the posterior pillars of fornix.
• The two hippocampi are connected to each other at their upper parts by the hippocampal commissure.
• The hippocampus represents an olfactory centre of higher order receiving fibres from the piriform lobe and its efferent fibres the fimbria and fornix reach the mammillary body.