ANATOMY

General Functional Areas of the Frontal Lobe

• The frontal lobe contains 4 general functional areas:

1. The primary motor cortex occupies much of the precentral gyrus. It contains many of the cells of origin of descending motor pathways and is involved in the initiation of voluntary movements.
2. The premotor area is made up of the remainder of the precentral gyrus together with adjacent portions of the superior and middle frontal gyri. It is also functionally related to the initiation of voluntary movements.
3. Broca’s area is in the opercular and triangular parts of the inferior frontal gyrus of the left hemisphere. It is important in the production of written and spoken language.
4. The prefrontal cortex is a very large area comprising the remainder of the frontal lobe. It is involved with what may very generally be described as personality, insight, and foresight.

The Parietal Lobe

• The parietal lobe extends from the central sulcus to an imaginary line connecting the top of the parietooccipital sulcus and the preoccipital notch.
• Inferiorly it is bounded by the lateral sulcus and the imaginary continuation of this sulcus to the posterior boundary of the parietal lobe.
• On the medial surface, it is bounded inferiorly by the corpus callosum and calcarine sulcus, anteriorly by the frontal lobe, and posteriorly by the parietooccipital sulcus.