Penile vascular cushions and erection.

Penile intimal cushions in the arteries and veins of five adults and one newborn were studied. In adults, they were present in approximately one-third of the muscular vessels seen on a single cross-section. No cushions were found in the newborn penis. We postulate that cushions play only a passive role in erection. Theories as to their pathogenesis are presented and the concept of linear stress as an adaptive agency is favored.