Parasagittal view of head through lateral wall of the nasal cavity. The lateral wall of the nasal cavity consists of projections of mucosa-covered turbinate bones: superior, middle, and inferior turbinates. Olfactory mucosa lines the upper portions of the medial and lateral nasal walls and neurofilaments of the olfactory nerves pass through tiny apertures in the cribriform plate to synapse in the olfactory bulbs. From there, olfactory information travels to the primary olfactory cortex within the olfactory tracts. Within the body of the sphenoid is the sphenoid sinus and sella turcica for the pituitary gland. The dorsum sellae and basilar portion of the occipital bone form the clivus, a slope of bone on which rests the brainstem. The corpus callosum, the primary commissural region of the brain consisting of white matter that connects the right and left cerebral hemispheres, is shown with its parts (from anterior to posterior): rostrum, genu, body, and splenium. The massa intermedia, which connects the right and left thalami across the midline of the third ventricle, is located posterior to the foramen of Monro and anterior commissure. The third ventricle is connected to the fourth ventricle via the narrow cerebral aqueduct that passes through the midbrain just anterior to the superior and inferior colliculi. (Image courtesy of AL Rhoton, Jr.)