DEFINITION OF ERECTILE DYSFUNCTION
The persistent inability to obtain or to maintain an erection sufficient for satisfactory sexual activity (intromission, pelvic thrusting and orgasm).

ANATOMIC CONSIDERATIONS
The corpora cavernosa extend from the mid-glans to the inferior surface of the ischial rami. They have a tough fibrous wall (tunica albuginea) enclosing the blood sinusoids. The corpora are covered by Buck's & Colle's fascia.

Arterial Supply to the penis is derived mainly from the 4 terminal branches of the internal pudendal artery
- Dorsal A: Glans penis
- Spongiosal (urethral) A: Corpus spongiosum, urethra, glans.
- Cavenosal (deep) A: Erectile tissue of corpora cavernosa through the helicine (spiral) arteries.
- Bulbar A: Bulbous urethra.

The penis is drained by three sets of veins:
- Superficial: Superficial dorsal vein, drains skin & S.C. tissue into superficial external pudendal into the saphenous vein.
- Intermediate: Deep dorsal vein, formed by 6-15 retrocoronal
veins, drains the mid & distal corpora cavernosa
--- emissary vs --- circumflex vs --- deep dorsal
--- periprostatic venous plexus.
- Deep: Cavernosal, Crural, urethral & bulbar veins drain proximal corpora cavernosa & corpus spongiosum
into the internal pudendal vein.
Nerve supply: S2-4
- Sensory: dorsal N. of penis --- pudendal N. --- sacral segments
- Motor:
Somatic: Pudendal N. ---- Bulbocavenous & ischiocavernous muscles
Parasympathetic: S2-4 --- pelvic nerve --- cavernosal Ns