Which cerebral artery is likely involved in a stroke patient with aphasia and right hemiparesis, with greater involvement of the arms and face than the legs?

Left Middle Cerebral Artery (MCA) Stroke

The stroke involves the left middle cerebral artery (MCA), specifically the superior division or proximal M1 segment. 1

Anatomical Localization

The clinical presentation of aphasia combined with right-sided hemiparesis affecting the arm and face more than the leg is pathognomonic for left MCA territory infarction. 1 This distribution pattern occurs because:

• The MCA supplies the lateral convexity of the cerebral hemisphere, including the motor and language cortex 1
• The motor homunculus representation shows that arm and face areas are located more laterally in the precentral gyrus (supplied by MCA), while the leg area is located more medially (supplied by anterior cerebral artery) 1
• Aphasia indicates left hemisphere involvement in right-handed individuals, as language centers (Broca's and Wernicke's areas) are located in the left MCA territory 1, 2

Key Distinguishing Clinical Features

The pattern of "arm and face greater than leg" weakness is the critical localizing sign:

• MCA strokes characteristically spare or minimally affect the leg because the leg motor cortex is supplied by the anterior cerebral artery (ACA), not the MCA 1
• If all three areas (face, arm, and leg) were equally affected, this would suggest internal capsule involvement rather than cortical MCA territory 3
• The presence of aphasia confirms cortical involvement rather than a subcortical lacunar stroke 1, 2

Vascular Territory Considerations

The left internal carotid artery (ICA) can produce identical symptoms to left MCA occlusion, as the MCA is the direct continuation of the ICA. 1 However, the clinical syndrome described is most specifically attributable to the MCA territory itself. 1

Research confirms that MCA involvement is associated with the most severe aphasia compared to other arterial territories (ACA or PCA), and these patients show significant improvement with speech therapy. 2

Common Pitfall to Avoid

Do not confuse this with brainstem stroke. Brainstem lesions would produce ipsilateral facial deficits with contralateral body deficits (crossed findings), not the purely contralateral pattern seen here. 3 The presence of aphasia also excludes brainstem localization, as language centers are cortical. 3