The primitive hypoglossal artery is present during embryological development, regresses during development, and may rarely persist as a persistent primitive hypoglossal artery[^1].
Embryology
The primitive hypoglossal artery normally regresses when the embryo is approximately 6 mm in size[^1].
Schematic illustration of the embryonic connections from the internal carotid artery to the longitudinal neural artery. Figure adapted from Wikipedia.
Schematic illustration of the persistent primitive hypoglossal artery. Figure adapted from Bruetman et al. 1963.
Blood supply
If a persistent primitive hypoglossal artery is present, it provides the main blood supply to the posterior circulation, and the Vertebral artery is hypoplastic or absent[^1].