[Erection disorders. I: Anatomical-physiological bases and diagnostic assessment].

During the past decade innovative research in physiology of erection and pathophysiology of impotence has brought a better understanding of the differential diagnosis and a new consideration of therapy in erectile dysfunction (ED). The basic anatomical structures and physiological mechanisms are described followed by a critical illustration of the various functional diagnostic tests. Intracavernosal injection with vasoactive agents proved to be the best functional screening test. The nocturnal continuous monitoring of penile tumescence and rigidity still appears to be of great value in the differential diagnosis of psychogenic impotence but is not frequently used as a routine investigation. Apart from the invasive methods as cavernosography, cavernosometry and selective penile arteriography the ultrasound examination using duplex scan or, in particular, the colored duplex scan (Angiodynography) turned out to be excellent tests to answer the vascular questions. For lack of an evident neurological test the diagnosis of neurogenic impotence is made by exclusion.