Frontal lobe

The frontal lobe is one of the four major lobes of the cerebral cortex. It is situated at the front of each cerebral hemisphere and is positioned anterior to the parietal lobe and above and anterior to the temporal lobes.

Two significant sulci in the cerebral cortex outline the boundaries of the frontal lobe. For example, there is a sulcus called the central sulcus on the outer side of the cerebral hemisphere, which separates the frontal lobe from the parietal lobe at the back. Another sulcus called the lateral sulcus (or Sylvian fissure) separates the frontal lobe from the temporal lobe at the back and bottom.

The frontal lobe contains three important sulci: the precentral sulcus, the superior frontal sulcus, and the inferior frontal sulcus. These sulci divide the frontal lobe into four significant gyri. The precentral sulcus is situated in front of the central sulcus and extends diagonally downward and forward from the upper edge of the cerebral hemisphere. Collectively, these sulci enclose the pre-central gyrus, which houses the primary motor cortex. This region is responsible for controlling voluntary movements of specific body parts.

Two additional sulci, known as the superior and inferior frontal sulci, are positioned horizontally and located in front of the precentral sulcus. These sulci divide the frontal region into three frontal gyri called the superior, middle, and inferior frontal gyri, which are aligned parallel to each other. In this area there are important motor zones. The upper part of the superior frontal gyrus, just in front of the precentral gyrus, contains the premotor area that is involved in motor planning. Moving down, there is the frontal eye field situated within the middle frontal gyrus, in front of the precentral gyrus. This area controls saccadic eye movements. Continuing further, we find the Broca's motor speech area located in the inferior frontal gyrus, also in front of the precentral gyrus where the representation of the face can be found in the motor homunculus. The frontal lobe's front region, including the frontal pole, is the most advanced part of the frontal cortex in terms of functionality, known as the prefrontal cortex. It is responsible for executive functions such as planning, decision making, working memory, personality expression, regulating social behavior, and controlling certain aspects of speech and language.

The frontal lobe cortex obtains its blood flow from two divisions of the internal carotid artery: the anterior cerebral arteries and the middle cerebral arteries. The smaller anterior cerebral artery caters to the upper and inner sections of the cortex, whereas the larger middle cerebral artery supplies blood to the lower and outer parts.