Lab 3 - The Ventricles and Blood Supply

External Topology of the Brain Stem

External Topology of the Brain StemOn the whole brain, REVIEW the major subdivisions of the central nervous system. The medulla (myelencephalon) is the most caudal division of the brain and is normally continuous with the spinal cord. The metencephalon consists of the pons and the cerebellum. Rostral to the pons is the midbrain (mesencephalon), which is distinguished by two anteriorly located columns of fibers, the crura cerebri or cerebral peduncles.

That portion of the diencephalon which you can see on the inferior surface of the brain is the hypothalamus. In this view, two small round elevations, the mammillary bodies (part of the hypothalamus), mark the caudal extent of the diencephalon and the optic chiasm marks its rostral border. The remainder of the brain, i.e., the cerebrum, constitutes the telencephalon. These five divisions (i.e., the medulla, metencephalon, midbrain, diencephalon, and telencephalon) together with the spinal cord, constitute the bulk of the central nervous system.