Persistent hypoglossal artery in the fetus.

The hypoglossal artery in a human fetus studied by post mortem angiography and microdissection is described. In contrast to the fetal form of the trigeminal artery which differs from the adult form by possessing branches supplying the pons and anastomotic branches to the cerebellar and internal auditory arteries, there were no major anatomical differences between the fetal and the adult form of the hypoglossal artery. The incompetence of the vertebral arteries in the presence of a hypoglossal artery is also emphasized.