The posterior temporal artery is a branch of the posterior cerebral artery supplying the inferior and medial temporal lobe including the parahippocampal gyrus, the fusiform gyrus, and the inferior temporal gyrus. In the dominant hemisphere (usually left) this territory includes Wernicke area (posterior superior temporal gyrus) when the posterior temporal branch extends far anterolaterally, and the fusiform face area and visual word form area are consistently within its territory.
Posterior temporal artery infarction in the dominant hemisphere produces Wernicke aphasia (fluent paraphasic speech with poor comprehension) when the language cortex at the posterior temporal-occipital junction is involved. Prosopagnosia (inability to recognise faces) results from bilateral fusiform gyrus infarction within this territory. The visual word form area (fusiform gyrus left) infarction produces pure alexia without agraphia from disconnection of the visual cortex from the language cortex. PCA infarction evaluation should assess all these specific territorial deficits.
Posterior cerebral artery infarction extending anterolaterally to the posterior superior temporal gyrus in the dominant hemisphere produces fluent Wernicke aphasia with paraphasias and poor comprehension alongside the expected hemianopia and hemisensory loss, indicating a large PCA territory infarction with language cortex involvement.
