The tenth vascular component in a rare form of the cerebral arterial circle of fetuses.

The ancient knowledge of the cerebral arterial circle (CAC) angioarchitecture could be supplemented by either a new or a forgotten old fact about it. Therefore, 7 cases of a rare form of the CAC of fetuses were described, where the so-called intermediate communicating artery, as an excess vessel into the posterior part, represented either its new vascular component or the developmental segment of this part. The paper aims at revealing the fetal history and morphological features of this 'underdeveloped' posterior part of the CAC during the 2nd and 3rd gestational trimesters, which could be of anatomical and clinical meaning in similar prenatal and/or postnatal cases. Copyright 2004 S. Karger AG, Basel