Types and Subtypes of the Posterior Part of the Cerebral arterial Circle in Human Adult Cadavers 361 Only one cadaver had cerebral infarction, while the others were on autopsy because of cardiac, respiratory, incidental and other causes of no cerebral pathology.Measurement of the outer diameter of the pre-communicating part of the posterior cerebral artery and the posterior communicating artery of both sides, as well basilar bifurcation angle was performed using ImageJ (http://rsb.info.nih.gov/ij/index.html).Statistical analysis of quantitative data is performed with PASW statistical software SPSS version 15.According to Kamath (1981), values of ≤ 0.5 and 1.0 mm for the posterior communicating and pre-communicating part of the posterior cerebral arteries are respectively used as hypoplastic calibers.