Surgical anatomy of the pudendal nerve and its branches in South Africans

Abstract

Dissection of the pudendal nerve (PN) and its branches in 71 cadavers revealed anatomic variations not previously described. Knowledge of this variation is necessary to prevent nerve injury resulting in sexual of sensory dysfunction. Because descriptions vary, this study re-evaluated the anatomy of the PN as implicated in perineal procedures in South Africans. The course of the PN from the gluteal region into the perineum was dissected in an adult sample of both sexes and of African and European ancestry. Distances between PN and branches to applicable landmarks were measured. Basic descriptive statistics and comparisons were carried out between groups. In 5/13 African females, the inferior rectal nerve (IRN) entered the gluteal region separately and in 12/13 cases it passed medial to the ischial spine with the PN. The dorsal nerve of the clitoris or penis (DNC/DNP) was closer to the bony frame in those of European ancestry. The IRN branches were more superficial in females, but deeper in males of European ancestry. In African females, a PN block and Richter stitch should be placed more medial. Outside-in transobturator tape procedures might endanger the DNC/DNP in obese individuals. In females of European ancestry the IRN branches are compromised during ischioanal abscess drainage. In males of European ancestry, the dorsal penile nerve block might be less effective. Predictions should be verified clinically.