The middle cerebral artery (MCA) is the largest of the three major arteries that channels fresh blood to the brain. It branches off the internal carotid artery. It supplies blood to lateral (side) areas of the frontal, temporal, and parietal lobes. The frontal, temporal, and parietal lobes control the sensory functions of the arms, throat, hands, and face.

The parts of the middle cerebral artery are:

  • Horizontal segment: This segment “burrows into” the brain tissue via branches called the lateral lenticulostriate arteries. These arteries are responsible for supplying blood to the basal ganglia. The basal ganglia are vast clusters of nerve cells, called neurons, that are responsible for involuntary movements.
  • Sylvian segment: Supplies blood to the temporal lobe and insular cortex. The temporal lobe is involved in the processing of sound. The insular cortex, also called the insula, regulates some motor function and helps pair emotions with experiences. The branches of the Sylvian segment may bifurcate (split in two) or trifurcate (split in three) into trunks. This area of the brain also contains the operculum, a covering of the brain, which extends from the insula in the direction of the cortex, the outer layer of the brain. The Sylvian segment is sometimes separated into the opercular segments and the insular segment.
  • Cortical segments: Provides blood to the cortex.

The middle cerebral artery is often obstructed, or blocked, during a stroke. Neuroimaging tools, such as CT scans, are commonly used diagnostic tests to determine strokes. Doctors search for acute middle cerebral thrombosis — a blood clot in the vessel —because this is a very sound indicator of thromboembolic middle cerebral artery obstruction, blockage of the middle cerebral artery that is caused by a clot or particle that came from somewhere else.