Brain Inferior Surface

The brain inferior surface is very irregular and contains a series of anatomical structures. These are the primitive parts in the evolution of Homo sapiens central nervous system. Although some of them are primitive, they are vital and essential for life. Looking at it with your naked eyes, you will notice the complex network of arterial blood vessels that supply the encephalon (all the CNS parts contained within the skull). On the other hand, the superior surface of the brain is regular, in a sense that it only includes the cerebral cortex, as it is convex like a dome.

Anatomical Description

The brain inferior surface lies on the sphenoid and inferior part of occipital bone. Not only do these bones have foramina (holes) for nerves, arteries, and spinal cord, but they also have irregular features, such as the sella turcica, on which the pituitary gland sits. But the three prominent features that make this aspect of the brain very irregular are the cerebellum, the brainstem, and the inferior portion of the temporal lobes, which curve around and extend towards the midline.

Below, you can see the inferior surface of brain. Every part is labeled and marked with arrows. There, you can see the allocortex, which include the paleocortex (rhinoncephalon: olfactory brain and olfactory bulb), the archicortex (hippocampus), and the parahippocampal girus. All these primitive structures are located on the inferior-posterior surface of the frontal lobes, and on inferior-medial surface of both temporal lobes.

At the center of the inferior aspect of encephalon, you can see a thick, cord-lice that extends downwards; it is the brainstem, which is made up of the midbrain, pons, and medulla oblongata. In front of the brainstem, there is the mammillary body, the tuber cinereum, the infundibulum, and the optic chiasma. In front of them, on the inferior frontal lobe, you can see the olfactory sulcus and the straight gyrus, lying medially. Finally, located behind the brainstem and bellow the cerebrum occipital lobe, there is the cerebellum, which is a massive structure of the encephalon, which functions a center of motor movement coordination.

 

Below, brain inferior surface, with the main arteries and cranial nerves labeled