penile prosthesis [L, penis + Gk, prosthesis, addition] , a device that can be surgically implanted in the penis to treat erectile dysfunction. Some such devices have mechanisms that control production of an erection. Penile prostheses can be semirigid (maintaining a continuous state of erection) or inflatable plastic cavernosal cylinders attached to a pump that forces fluid from a reservoir into the cylinders, producing an erection.
