[Local ultrastructural characteristics of the intracerebral arteries of human fetuses].

In 36 human fetuses (16 to 36 weeks of gestation) the ultrastructure of arterial vessels was investigated in the occipital and parietal hemispheres and midbrain tegmentum. During the antenatal ontogenesis the local features of the vessel wall structure were found, especially in the muscular layer. As it remained more differentiated in midbrain than in forebrain up to the end of gestation, more frequent forebrain stroke localization in infancy seems structurally dependent.