Medial surface of cerebral hemisphere

The medial surface of cerebral hemisphere has several significant sulci and gyri. In the middle, we can observe the largest brain commissure, which is a structure shaped like the letter C called the corpus callosum. It surrounds the body of the lateral ventricle and connects the right and left cerebral hemispheres. The corpus callosum is divided into four parts from font to back: the rostrum, genu, body, and tail (splenium). Encircling the corpus callosum is a curved C-shaped gyrus called the cingulate gyrus, which is part of the limbic cortex and associated with emotions. Between the corpus callosum and cingulate gyrus, there is a groove called the callosal sulcus, while above the cingulate gyrus, there is a groove called the cingulate sulcus. This latter sulcus separates the medial extensions of frontal and parietal lobes superiorly from cingulate gyrus inferiorly.

An invagination of central sulcus can be seen encroaching onto the medial surface of cerebral hemisphere. It is bounded by the medial extensions of precentral gyrus in the front and the post-central gyrus in the back. Together, on the inner surface of the cerebral hemispheres, these extensions form the paracentral lobule. The paracentral lobule contains the motor and sensory representation of the lower legs, which are part of the motor and sensory homunculi. Therefore, if a stroke affects the anterior cerebral artery, which supplies blood to the medial cortex, it could lead to weakness and/or sensory loss in the lower limbs while sparing the upper limbs and face. The paracentral lobule also houses the neural center that controls urination.