Middle Cerebral Artery (MCA)

Summary

The middle cerebral artery, or MCA for short, is a major blood vessel that supplies the cerebral cortex of the brain. Blockages of this artery in the context of a stroke leads to damage to both the motor and sensory cortices of the brain. In particular, this leads to motor and sensory deficits in the upper limbs and face. Additional neurological deficits can vary depending on the side of the brain that is affected. If the stroke occurs on the dominant side of the brain, patients can present with aphasia, or an impaired ability to speak. This aphasia can be split further depending on the location of the infarct. If the stroke occurs in the superior division of the middle cerebral artery, patients will exhibit Broca’s aphasia. If the infarct occurs in the inferior division, then patients will exhibit Wernicke's aphasias, which is often associated with a visual field defect in the right superior quadrant. Finally, if the MCA stroke occurs in the non-dominant hemisphere, patients may present with hemineglect.

Key Points

• Middle Cerebral Artery (MCA)
  • Largest cerebral artery
    • Most commonly involved in cerebrovascular accidents
  • Area of Lesion
    • Motor and sensory cortices
      • Supplies parietal and temporal regions of the brain
  • Presentation
    • Mixed weakness/paralysis + sensory loss
      • Contralateral face + upper extremities
      • Lower extremity mostly spared
    • Aphasia (inability to speak)
      • If dominant hemisphere (usually left) is affected
      • Frontal lobe (brocas) aphasia if superior division of MCA affected
      • Temporal lobe (wernicke) aphasia if inferior division of MCA affected
        • associated with right superior quadrant visual field defect
          • due to temporal lobe involvement and damage to optic radiations
    • Hemineglect
      • If non-dominant hemisphere is affected (usually right)