Splenium of corpus callosum

The splenium of corpus callosum is the thick, rounded posterior end of the corpus callosum, continuous anteriorly with the body through the narrowed posterior region known as the isthmus.

It contains commissural fibres derived predominantly from the posterior parietal, inferior temporal and occipital cortices of the two cerebral hemispheres (including the temporo-parietal-occipital junction). Many fibres curve backwards into the occipital lobes, forming the forceps major, which provides important interhemispheric connections between the occipital cortices, particularly visual association areas. Some callosal fibres also contribute to the tapetum, which extends along parts of the posterior and inferior horns of the lateral ventricles.

Relationship to nearby structures

• Inferiorly, the splenium lies superior to the hippocampal commissure (commissure of the fornix). The latter lies between the fornices and has a midline attachment to the undersurface of the splenium. This way, the splenial and the hippocampal commissural fibres cross the midline in close proximity.

• The pineal region and posterior part of the third ventricle lie further inferiorly.

• Superiorly, the splenium of corpus callosum is related to the posterior callosal sulcus and cingulate/retrosplenial region.