Embryonal and fetal development of capillaries: microangiographic investigations. I. The brain stem.

The prenatal development of the intracerebral capillaries within the brain stem was systematically examined by a special microangiographic technique in 69 embryos and fetuses of cattle and pigs between 4 and 17 weeks of gestation. The microradiograms were compared with the corresponding histological slices. The different developmental stages and morphological patterns of vascularization are related to the local stage of maturation, histological structure and metabolic activity of the nervous tissue.