For this week’s discussion I am going to talk about the brain and its major subdivisions and landmarks. There are two directional terms that are used when referring to the brain. The first is rostral, which means “towards the forehead” (Saladin, 2015). The second term is caudal, which means “toward the spinal cord” (Saladin, 2015).
The brain can be divided into three major portions: the cerebrum, cerebellum, and the brainstem (Saladin, 2015). The cerebrum is by far the largest portion of the brain, about 83% of the total volume, and can be further subdivided into two hemispheres, the left cerebral hemisphere and the right cerebral hemisphere (Saladin, 2015). The hemispheres are separated by a long groove called the longitudinal fissure (Saladin, 2015). Each hemisphere is made up of think folds called gyri, and the shallow grooves that separate each gyri are called sulci (Saladin, 2015). Furthermore, each hemisphere contains the different lobes of the brain, one for each hemisphere. From rostral to caudal, there are the frontal lobes, temporal lobes (on the side above where the ear would be), the parietal lobes, and the occipital lobes (Saladin, 2015). At the bottom of the longitudinal fissure, deep inside the brain, there lies a bundle of nerve fibers called the corpus callosum (Saladin, 2015).
Next, there is the cerebellum, the second largest portion of the brain, about 10% of the brain’s volume (Saladin, 2015). It is also made up of gyri and sulci, and contains about 50% of the brain’s neurons (Saladin, 2015). The cerebellum is located underneath the occipital lobe in the posterior cranial fossa, and is separated from the cerebrum by the transverse cerebral fissure (Saladin, 2015).
Finally, there is the brainstem. It is the smallest part of the brain, and its major components, from rostral to caudal, are the diencephalon, midbrain, pons, and the medulla oblongata (Saladin, 2015). The brainstem is the part of the brain that branches down and connects with the spinal cord (Saladin, 2015).
For remembering the anatomy of the brain, I really liked the example the textbook used. The text describes the brainstem being oriented like a stalk with the cerebrum and cerebellum being perched on top like a mushroom cap (Saladin, 2015).