Axial T2 MRI. Shows strokes between the MCA and ACA distributions on the right. Vascular territories highlighted. The superior frontal sulcus is a helpful anatomical landmark of the separation between the MCA and ACA territories.
Watershed (ACA/MCA) Stroke
Watershed strokes occur from poor perfusion of regions that are susceptible to low flow states -- the areas of irrigation between typical vascular territories.
Vascular insufficiency within arterial borderzones produces borderzone infarcts (aka watershed strokes).
Patients with a watershed stroke between the anterior cerebral artery ACA and middle cerebral artery MCA develop weakness of their proximal arms and legs with preservation of hand and feet strength – they act like a “man in a barrel.”
From an anatomical perspective, the ACA supplies the medial one third of the superior cerebrum and the MCA supplies the lateral two thirds; the superior frontal sulcus separates the MCA and ACA supply.
The somatotopic sensorimotor area that corresponds to the borderzone between the MCA and ACA encodes the proximal arms and legs.
Related Anatomical Structures: