<prompt> Syphilitic aneurysm mostly involve ?Arch of aoaDescending aoaAbdominal aoa above the renal aeriesNone  <response>: Ans. is NoneSyphilitic Aneurism o Also known as leuetic aneurysm.o This is due to obliterative endaeritis that involves vaso vasorum of aoa in the teiary stage of syphilis. o It usually affects the proximal ascending aoa, paicularly the aoic ring.Syphilitic aoitis may occasionaly involve the aoic arch or descending aoa.o Contraction of fibrous scar with in the vessel wall may lead to wrinkling of the intervening segments of arotic intima Tree - barking.o There is characteristic linear calcification of the ascending aoa.o Aoic valve insufficiency results in cardiac hyperophy and the name given to such hea is COR bovinumCow hea because of increased size of hea. 