Pudendal canal: surgical anatomy and clinical implications.

The anatomy of the pudendal canal (PC) was studied in 26 cadavers: 10 stillborn and 16 adults (mean age, 48.2 years). Two approaches were used to expose the PC: gluteal and perineal. The PC was an obliquely lying tube with a mean length of 0.8 cm in the stillborn and 1.6 cm in the adult cadavers. It started at a mean distance of 0.8 cm from the ischial spine in the stillborn and of 1.6 cm in the adult cadavers, and ended at a mean distance of 0.7 cm and 2.6 cm, respectively, from the lower border of the symphysis pubis. The PC wall was formed by the splitting of the obturator fascia and not by the lunate fascia. The PC contained the pudendal nerve and vessels embedded in loose areolar tissue. The three branches of the neurovascular bundle arose inside the canal in all but three cadavers. The wall of the PC consisted of collagen and elastic fibers, whereas that of the obturator fascia consisted of collagen only. The PC seems to be structurally adapted to serve certain functions. The criss-cross textile arrangement of collagen fibers in its wall allows the canal to change its shape in response to changes in pudendal vessels that occur during sexual activity. The elastic recoil may not only help to "pump" the blood up the pudendal vein, but also to prevent PC subluxation. The PC may, furthermore, act as a "pulley" for the neurovascular bundle. The pulley action may be disrupted by disordered pelvic floor muscles or defecation. Knowledge of the precise anatomy of the PC is necessary to carry out PC decompression in the treatment of PC syndrome.