Diagrams

The superior (upper or suprasylvian) MCA branch gives rise to several arteries that supply much of the lateral and inferior frontal lobe and the anterior lateral parts of the parietal lobe. The inferior (lower or infrasylvian) MCA branch gives rise to arteries that supply the lateral temporal lobe including its anterior tip and the amygdala, posterior parietal and much of the lateral occipital lobe.

Clinical Note: Emboli can also lodge in one of the major cortical branches of the MCA, as well as in the smaller arteries that they will subsequently form.

Superior branches of MCA supply these key functional areas:
  • Primary motor cortex for face and arm, and axons originating in the leg as well as face and arm areas that are headed for the internal capsule as part of the corticobulbar or corticospinal tracts
  • Broca's area and other related gray and white matter important for language expression--in the language-dominant (usually left) hemisphere
  • Frontal eye fields (important for 'looking at' eye movements to the opposite side)
  • Primary somatosensory cortex for face and arm
  • Parts of lateral frontal and parietal lobes important for 3-D visuospatial perceptions of one's own body and of the outside world, and for ability to interpret and express emotions--in the nondominant (usually right) hemisphere

Inferior branches of MCA supply these key functional areas:
  • Wernicke's and other related areas important for language comprehension in the language-dominant (usually left) hemisphere
  • Parts of the posterior parietal lobe important for 3-D visuospatial perceptions of one's own body and of the outside world, and for the ability to interpret emotions--in the nondominant (usually right) hemisphere
  • Optic radiations, particularly fibers that represent information from the contralateral superior quadrants and loop forward into the temporal lobe (they are located anterior and lateral to the temporal horn of the lateral ventricle) as they travel from the lateral geniculate body to the striate cortex, located in the occipital lobe