The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries. Structure The posterior cerebral artery is subdivided into 4 segments: P1: pre-communicating segment Originated at the termination of the basilar artery May give rise to the artery of Percheron if present P2: post-communicating segment From the PCOM around the midbrain Terminates as it enters the quadrigeminal ganglion Gives rise to the choroidal branches (medial and lateral posterior choroidal arteries) P3: quadrigeminal segment Courses posteromedially through the quadrigeminal cistern Terminates as it enters the sulk of the occipital lobe P4: cortical segment Within the sulci of the occipital lobe The branches of the posterior cerebral artery are divided into two sets, ganglionic and cortical. Central branches The following are central branches of the PCA, also known as perforating branches: Thalamoperforating and thalamogeniculate or postero-medial ganglionic branches: a group of small arteries which arise at the commencement of the posterior cerebral artery: these, with similar branches from the posterior communicating, pierce the posterior perforated substance, and supply the medial surfaces of the thalami and the walls of the third ventricle. Peduncular perforating or postero-lateral ganglionic branches: small arteries which arise from the posterior cerebral artery after it has turned around the cerebral peduncle; they supply a considerable portion of the thalamus. Posterior (choroidal) branches The posterior choroidal branches of the posterior cerebral artery are sometimes referred to as a single posterior choroidal artery. Medial posterior choroidal branches: run forward beneath the splenium of the corpus callosum, and supply the tela choroidea of the third ventricle and the choroid plexus. Lateral posterior choroidal branches: small branches to the cerebral peduncle, fornix, thalamus, caudate nucleus, and choroid plexus of the lateral ventricle. Cortical branches The cortical branches are: Anterior temporal, distributed to the uncus and the anterior part of the fusiform gyrus Posterior temporal, to the fusiform and the inferior temporal gyri Lateral occipital, which branches into the anterior, middle and posterior inferior temporal arteries Medial occipital, which branches into the: Calcarine sulcus, to the cuneus and lingual gyrus and the back part of the convex