Nō to shinkei = Brain and nerve
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We reported a rare case of the posterior inferior cerebellar artery arising from the internal carotid artery directly. A 33-year-old male was admitted to our hospital with the complaint of throbbing type headache. CT showed no abnormal findings. ⋯ We diagnosed it as a kind of variant of the persistent primitive hypoglossal artery. The persistent primitive hypoglossal artery is composed of the proximal segment derived from the primitive hypoglossal artery, and the distal segment consisting of portions of the lateral anastomotic channels (primitive lateral basillo-vertebral anastomosis) which give rise to the posterior inferior cerebellar artery. We speculated that this variant resulted from the persistence of the proximal segment, which communicated with the stem of the posterior inferior cerebellar artery via the distal segment, and next, the disconnection of the posterior inferior cerebellar artery origin with the vertebral artery due to the aplasia of right vertebral artery and the involution of the distal segment connected to the basilar artery.