Penile Anatomy
The penis is two corpora cavernosa plus a corpus spongiosum (which carries the urethra and forms the glans) — each wrapped in tunica albuginea, all bound by Buck's fascia, supplied by the internal pudendal arteries, and draining skin-first to inguinal nodes.
The big picture
The penis is composed of two corpora cavernosa and a corpus spongiosum, the latter containing the urethra. The corpus spongiosum enlarges distally to form the glans penis. Each corpus is enclosed in a fascial sheath, the tunica albuginea, and all three are surrounded by a thick fibrous envelope, Buck's fascia.
Tunica albuginea wraps each corpus; Buck's fascia binds all three; the internal pudendal artery supplies them; penile skin drains to inguinal nodes, the glans to subinguinal/external iliac nodes.
Mechanism pathway
Tap any step to see why it happens.
