The Parieto-Occipital Artery Revisited: A Microsurgical Anatomic Study

The parieto-occipital artery (PoA) is the terminal posterior cerebral artery branch, which typically runs in the parieto-occipital sulcus. Previous studies have highlighted variation in the PoA origin and branching pattern and their clinical implications. Nevertheless, PoA anastomoses have not been systematically investigated. The present study aimed to assess whether putative variation in PoA origin and its branching as well as anastomotic pattern is associated with differences in demographic/anthropometric variables.

In 15 cadaveric heads, PoA anatomic features were quantified and assessed in relation to demographic/anthropometric variables.

The mean distance of PoA origin from the posterior limit of the splenium and the occipital pole (OP) is 3.1 and 53.1 mm, respectively. The latter is significantly longer in taller individuals. The PoA supplies a mean of 10.5 and 9.1 branches to the precuneus and cuneus, respectively. PoA anastomoses primarily involve the precuneal artery complex (PAc) and the calcarine artery. The analysis indicated significant, positive correlations between the distance of PoA origin from the OP and the number of PoA anastomoses and between the number of PoA precuneal and cuneal branches.

Although the PoA invariably supplies the precuneus and almost always the cuneus, its direct contribution to the former seems inferior to PAc. Nevertheless, the PoA frequently shows putative collateral supply networks to the precuneus and cuneus via anastomoses with the PAc and calcarine artery, respectively. The distance between PoA origin and OP varies with an individual's height; the frequency of intrahemispheric PoA anastomoses varies with its site of origin.