[The ultrastructural changes in the collagenous-elastic skeleton of the wall of the cerebral vessels in spasm in the acute period of a subarachnoid hemorrhage].

Electron microscopic study of arteries in spasm and ischemia of the brain revealed substantial ultrastructural changes in the vascular wall. The changes are characterized by varying thickness, edema, dissociation of fibrillar and amorphous components of internal elastic membrane of the arterial wall, by lesion in the network of collagen fibers on its inner surface, by the presence of defibrotic and uncoiled collagenous fibers of the adventitia. The changes are followed by the impairment of the arterial skeleton and hence they lead to their altered elastic properties.