[The pathomorphology of the arteria primitiva trigemina, together with some critical comments on the pathomorphology of its adjacent structures and the morphological cerebral complications (author's transl)].

In the light of six self-reported observations an account is given on the pathomorphology and pathohistology of the arteria primitiva trigemina including morphological changes of neighbouring organs and tissue structures as well as of the brain which are directly casused by the anastomosis. Furthermore, our own findings and those described in the pertinent literature are compared. In three of our own cases considerable calcification of the intima and media of the persistent artery have been demonstrated histologically, On the other hand only a slight involvement of the blood vessel from which it originates and of that one into which it flows as well as of the other arteries of the base of the brain has been observed. This suggests to be the result of special flow and pressure relationships of the blood, and interpreted as locus minoris resistentiae. The discrepancy between the frequency of the neuroradiological demonstration and the clinico-neuropathophysiological importance of the anastomosis, on the one hand, and the obtaining of neuropathological autopsy findings, on the other, has been pointed out.