The middle cerebral artery is one of the three major arteries that transport the supply of freshly oxygenated blood from the heart to the brain. There are actually two middle cerebral arteries as each of the arteries of the brain is effectively mirrored in the two hemispheres of the brain. Thus, there is a left and a right middle cerebral artery. Large areas of the frontal, parietal, and temporal lobes are irrigated by this artery and its branches and subdivisions. Since the middle artery is the largest of the arteries in the brain, it is involved in most stroke events.
The cerebral segment of the internal carotid artery forms the middle cerebral artery and the posterior cerebral artery. The middle cerebral artery on each side of the brain then passes near and sometimes follows along the sphenoid bone of the skull. In this section, many smaller arteries branch off and carry blood to the basal ganglia which functions in eye movement, muscle movement, and learning. The next segment of the middle cerebral artery lies along the insular cortex, i.e., an extended infolding of the cerebral cortex. The main artery splits here into two or three branches that begin to travel toward the cerebral cortex.
Those larger branches divide into many smaller branches that deliver the nutrient rich blood to the cortex. The areas of the frontal lobe that are supplied by the middle cerebral artery include the middle frontal gyrus and the inferior frontal gyrus. The anterior and posterior central gyri as well as the gyri of the inferior parietal lobe are also irrigated by branches of the middle cerebral artery. In the temporal lobe, the superior and middle gyri receive blood through these same arterial branches.
A stroke that occurs in the middle cerebral artery can have different potential effects depending on which part of the brain is normally supplied by the blocked or ruptured arterial branch. When the frontal cortex is damaged, certain body parts like the arm, hand, or face may experience paralysis. Language processing and expression may also be affected, and thinking and behavior may become rigid. In the parietal lobe, symptoms could include difficulty reading and associating words with objects as well as confusion in spatial relations between body parts that leads to loss of coordination. Temporal lobe processes that could be interrupted by stroke are categorization, facial recognition, and the interpretation of spoken language.