**1. Introduction**

Penetrating aortic ulcers were initially described by Shennan in 1934 [1]. Shumacker and King reported the first operative repair of a ruptured descending aorta secondary to a penetrating aortic ulcer in 1959 [2]. The clinical and pathologic entity of penetrating aortic ulcers was not established, however, until 1986 by Stanson [3]. Since that time, the body of literature on this disease has increased significantly. This chapter provides a broad overview of penetrating aortic ulcers.
