[Plastic properties of the venous bed of the brain following disengagement of the external jugular veins at different stages of ontogenesis].

The capacity of the venous bed in the brain being great, even inconsiderable changes of the vein lumen can cause severe changes in the blood circulation without an enlargement of the cranial cavity volume. The progressing venous stagnation in the brain is a severe disease of not only the brain but also the whole organism. So, we attempted to study the character of compensatory redistribution of the pial venous system of the cerebrum in occlusion of both exterior jugular veins and to establish its developmental accomodative properties. The work has been performed on 45 dogs. The plasticity of the cerebral pial veins was found to drop with age, their reserving capacity-to grow and their carrying capacity-to decrease. Three successive phases are characteristic of the compensatory-adaptational changes: diffuse dilatation of the venous network, appearance of collaterals and their development against the background of reduction of the surrounding venous network.