Berry aneurysm - defect lies in -: (A) Degeneration of internal elastic lamina, (B) Degeneration of media/muscle cell layer, (C) Deposition of mucoid material in media, (D) Low grade inflammation of vessel wall
Answer is B. Berry's aneurysm is a brain aneurysm caused due to a defect in media. Berry aneurysms arise at the point of weakness in the arterial media, especially branch points in the circle of Willis.
There is a congenital defect in tunica media of cerebral vessels which leads to aneurysm formation.