Veterinary Gross Anatomy-II

CORPUS CALLOSUM

• It is the largest mass of commissural fibres that connect the two cerebral hemispheres.
• The fibres spread out laterally in a radiating manner in the central white mater of each hemisphere.
• These fibres are crossed by the ascending fibres of the internal capsule.
• The central part or truncus between the two hemispheres appears as arched structure, sloping downwards and forwards and curving downwards at the anterior and posterior ends.
• The anterior end or genu bends downwards and backwards and thins out to form the rostrum which is continuous with the lamina terminalis closing the anterior part of the third ventricle.
• The posterior end or splenium lies at a higher level than the genu.
• The dorsal surface of the corpus callosum is convex. It is covered dorsally by a thin layer of gray mater indusium griseum and shows two longitudinal striae -medial and lateral on each side of median line.
• The indusium griseum and the longitudinal striae are the ill developed parts of the rhinencephalon. The ventral face is concave and forms the roof of the lateral ventricles and the septum lucidum attached to it medially.
• The septum lucidum is the median partition between the two lateral ventricles.
• Its dorsal border is convex and is attached to the corpus callosum and the concave ventral border is attached to the fornix.
• Its anterior part is received into the genu and it becomes narrow behind at the splenium.

Cerebral hemisphere sliced to show the corpus callosum

Gray matter White matter Corpus callosum