<P> The anterior cerebral arteries are in contact with the under surface of the rostrum; they then arch over the front of the genu, and are carried backward above the body of the corpus callosum . </P> <P> The body or truncus of the corpus callosum is between the splenium and the genu . A narrowed part between the body and the splenium is known as the isthmus of the corpus callosum . </P> <P> On either side of the corpus callosum, the fibers radiate in the white matter and pass to the various parts of the cerebral cortex; those curving forward from the genu into the frontal lobe constitute the forceps anterior, and those curving backward into the occipital lobe, the forceps posterior . Between these two parts is the main body of the fibers which constitute the tapetum and extend laterally on either side into the temporal lobe, and cover in the central part of the lateral ventricle . The tapetum and anterior commissure share the function of connecting left and right temporal lobes . </P> <P> Thinner axons in the genu connect the prefrontal cortex between the two halves of the brain; these fibres arise from a fork - like bundle of fibers from the tapetum, the forceps anterior . Thicker axons in the mid body, or trunk of the corpus callosum, interconnect areas of the motor cortex, with proportionately more of the corpus callosum dedicated to supplementary motor regions including Broca's area . The posterior body of the corpus, known as the splenium, communicates somatosensory information between the two halves of the parietal lobe and the visual cortex at the occipital lobe, these are the fibres of the forceps posterior . </P>

Where is the corpus callosum what structure does it enclose