The penis is an external organ of the male reproductive system. Sexual intercourse – During erotic stimulation, the penis undergoes erection, becoming engorged with blood. The root contains three erectile tissues (two crura and bulb of the penis), and two muscles (ischiocavernosus.
The penile shaft is composed of 3 erectile columns, the 2 corpora cavernosa and the corpus spongiosum, as well as the columns' enveloping fascial layers, nerves, lymphatics, and blood vessels, all covered by skin (see the following images). The paired corpora cavernosa contain.
Several branches of the pudendal nerve innervate the penis, including the dorsal nerve of the penis. The pudendal nerve carries axons.