Arterial Supply to the Left Posterior Parietal Lobe
The left posterior parietal lobe is supplied by branches of the left middle cerebral artery (MCA), specifically the angular artery and posterior parietal branches from the superior trunk of the MCA. 1
Primary Arterial Supply
The posterior parietal region receives its blood supply through a dual arterial system:
Middle Cerebral Artery (MCA) branches supply the lateral surface of the posterior parietal lobe, with the anterior parietal and posterior parietal branches arising predominantly from the superior trunk of the MCA 2
The superior third of the lateral parietal surface receives additional supply from the superior parietal branches of the pericallosal and callosomarginal arteries (branches of the anterior cerebral artery) 2
Clinical Correlation from Case Evidence
A documented case demonstrates this vascular anatomy: a 17-year-old patient with left parietal stroke in the posterior left MCA territory had an occluded left M3 segment, confirming that the posterior parietal territory is supplied by distal MCA branches 1
Anatomical Boundaries
The posterior parietal lobe's arterial supply follows a predictable pattern:
Lower two-thirds of the lateral parietal surface: supplied by central, precentral, and anterior parietal branches from the MCA superior trunk 2
Superior third and medial surface: supplied by branches from the anterior cerebral artery system 2
Important Clinical Caveat
While the posterior cerebral artery (PCA) primarily supplies the occipital lobe, anatomical variations exist where the PCA may contribute to posterior parietal perfusion in some individuals, particularly when fetal PCA variants are present (occurring in approximately 11% of hemispheres) 3. However, the primary and consistent supply to the posterior parietal lobe remains the MCA branches 1, 2.