Figure 7-8
Hemisected brain (right half).

Figure 7-9
Insula revealed laterally under retracted cerebrum. Coronal section at level of the dashed line shows insular cortex.

Review Figure 7-2. Keep in mind the specimen you are using may have the filmy arachnoid around it. Identify the two large right and left cerebral hemispheres. The two cerebral hemispheres are separated from one another by a deep mid-sagittal longitudinal fissure . The floor of this fissure is the corpus callosum which is made of nerve fibers that connect the two cerebral hemispheres.

At the posterior inferior surface of the cerebrum identify the cerebellum also composed of two hemispheres. Find the brain stem on the base of the cerebrum (Figure 7-3). Can you see any of the cranial nerves as they emerge from the brain stem?

Look at the cerebral and cerebellar hemispheres and the brain stem using a hemisected brain (Figure 7-8).

Begin by identifying the various sulci, notches and fissures that separate the lobes of the cerebrum and then identify the lobes themselves. Some anatomists include another area of the cerebral cortex, the insula as a separate lobe. The insula is very hard to see as it is buried beneath the other lobes of the brain. (Figure 7-9)