Microsurgical Anatomy of the Precuneal Artery: Does It Really Exist? Clarifying an Ambiguous Vessel Under the Microscope

BACKGROUND: The ambiguous term precuneal artery (PA) has several synonyms and anatomic definitions. OBJECTIVE: To examine the arteries of the precuneus and describe the PA and its branching pattern. We defined the PA as the principal arterial supplier of the precuneus. METHODS: Twenty formalin-fixed, colored latex–injected cadaveric heads were studied with the aid of an operating microscope and microsurgical instrumentation. After removal of the cerebrum from the cranial vault, we examined this vessel's anatomy. Anatomic features of the PA were investigated and assessed in relation to demographic and anthropometric variables. RESULTS: The PA was always a pericallosal artery branch and, more specifically, the superior internal parietal artery (SIPA) in 86.84%, the inferior internal parietal artery in 2.63%, and their common stem in 10.53% of specimens. Anastomosing interhemispheric branches between the PAs were present in 20% of cases. Compared with the right PA, the left anastomosed nearly 3 times more often with the ipsilateral posterior cerebral artery. The average distance of the PA's origin from the posterior limit of the splenium was shown to be 9.4 mm longer in elderly individuals compared with younger ones. CONCLUSION: The term PA complex (rather than PA) can better describe the principal arterial supplier of the precuneus, and the SIPA, inferior internal parietal artery, and their common stem were shown as the 3 contributing arteries, with the SIPA predominating. The average distance of the PA complex origin from the splenium's posterior limit shows significant variation with respect to age. ABBREVIATIONS: a, anastomoses of precuneal branches with the contralateral hemisphere parameter ACA, anterior cerebral artery ACoA, anterior communicating artery ARCS, ascending ramus of the cingulate sulcus b, precuneal branches anastomosing with the ipsilateral posterior cerebral artery parameter; posterior cerebral artery BMI, body mass index c, precuneal branches at the medial hemispheric surface parameter CC, corpus callosum d, length of the ascending ramus of the cingulate sulcus parameter e, distance of the precuneal artery origin from the posterior limit of the corpus callosum parameter IIPA, inferior internal parietal artery PA, precuneal artery PCA, posterior cerebral artery PcA, pericallosal artery SIPA, superior internal parietal artery