Posterior Cerebral Artery, Gross Anatomy

Description

Centered on the posterior circulation, the posterior cerebral artery (PCA) is traced from its origin at the basilar artery bifurcation as the P1 segment, coursing posteriorly around the midbrain within the ambient cistern. Distal to the posterior communicating artery junction, the P2 segment sweeps laterally and posteriorly along the cerebral peduncle toward the tentorial edge, then continues into the P3 segment in the quadrigeminal cistern as it approaches the medial temporal and occipital lobes. Neighboring landmarks you would expect in this context include the superior cerebellar artery inferior to P1, the oculomotor nerve passing between major trunks, and the venous counterparts in the perimesencephalic region. Clear segmental labeling keeps the spatial relationships unambiguous. Segment anatomy matters because PCA infarcts do not behave like generic posterior strokes. Proximal P1 occlusion can compromise thalamoperforators and produce contralateral hemisensory loss or altered consciousness, while more distal P2 to P3 territory ischemia classically yields homonymous hemianopia from calcarine cortex involvement, sometimes with macular sparing. Aneurysms at the P1 to posterior communicating artery region also carry a distinctive risk profile for third nerve palsy and subarachnoid hemorrhage, so distinguishing P1 from P2 is not academic. Small vessel branches count here. Educators can drop this figure directly into neuroanatomy and neurovascular modules to teach PCA segments, cisternal pathways, and the correlation between arterial territory and visual field deficits. It also suits stroke conference slides, neurosurgical or endovascular pre-brief materials, and textbook layouts that need clean P1, P2, P3 segmentation without crowding. Anatomical accuracy verified by SciePro's Medical Advisory Board.