Histological and morphometric observations on the reticular fibers in the arterial beds of patients with ruptured intracranial saccular aneurysms.

Histological and morphometric studies on the collagenous, reticular, and elastic fibers of the tunica media were performed on the middle cerebral and brachial arteries of patients with ruptured intracranial saccular aneurysms and controls. There was no difference between aneurysm patients and controls in the amount of collagenous and elastic fibers. The amount of reticular fibers was, however, reduced about 35% in aneurysm patients within both the middle cerebral artery (P less than 0.01) and the brachial artery (P less than 0.02). The reticular fibers were irregularly distributed and often appeared shorter and coarser than normally. The observations point to a generalized abnormality of the arterial bed in some patients with rupture of saccular aneurysms.