Sumit Karia MD
The Common Vein Copyright 2010
Definition
Structure
It is bounded between the central fissure posteriorly and the precentral fissure anteriorly. It extends from the supero-medial border of the hemisphere to the posterior ramus of the lateral fissure, with which it communicates through Its inferior extremity (which is called the frontal operculum). Through this operculum, it unites with the prefrontal gyrus. On the superior extremity, it will also unite with the same gyrus.
Pyramidal cells of layer V constitute most of the pyramidal (corticospinal) tract, which is the main cerebral efferent motor system.
Function
Acts as the primary motor cortex, participating in control of mechanical actions of movement. Many of the corticospinal tract neurons are located in this gyrus. Their leave the motor cortex and travel down in the internal capsule to terminate on motor neurons in the spinal cord.
All motor activity needs some type of sensory guidance, and that is why the convolution is connected with several areas of the brain that are responsible for sensory, visual and auditory perceptions as well as the cerebellum.
Disease
The frontal lobe is supplied by the anterior cerebral artery. In the more deep regions, the blood comes from the superior division of the middle cerebral artery. A stroke causing a frontal lobe lesion in this area, provoked by insufficiency of this vessel may lead to motor abnormalities that are mostly evidenced by weakness/paresis/spasticity of contralateral extremity muscles. In the language-dominant hemisphere, a disturbance may develop in the motor components of speech.
Lesions in the premotor cortex can result in weakness, spasticity, and increased stretch reflexes.