Central nervous system disorders

IV./2.4.: Berry aneurysm

IV./2.4.1. Vascular predisposing factors of the development of berry- and sacciform aneurysms

It is a special structural (constitutional) characteristic of the cerebral, basal arteries that at the bifurcations, the wall of the vessels are constituted from tunica intima, fenestrated internal elastic lamina, and loose tunica adventitia, thus, at the bifurcations, multiple, nodal smooth muscle defects, and the lack of tunica media – to a variously severe extent- are frequent. At many times, even the external elastic lamina – as an external structural support- is also missing in pathologic parts of the vessels, which is another locus minoris resistentiae. The weak wall structure of these vessels cannot stand the mechanic, hit-like pressure of the blood column, and this is how circumstantial dilatation develops over time.