Morphology and morphometry of pudendal nerve in East Indian population with surgical implications: a cadaveric study

Pudendal nerve entrapment clinically has a wide spectrum of presentation ranging from urinary to anorectal and sexual dysfunction. The caliber of the pudendal nerve should be matched with calibre of donor nerve for a successful nerve transfer. Hence, we aimed at evaluating the morphology, dimensions of pudendal nerve at various sites of entrapment and certain trajectory distances to approach the pudendal nerve surgically. The study was conducted at Department of Anatomy at a tertiary care hospital and medical college. A detailed dissection of pudendal nerve was done and the morphology and morphometry of the pudendal nerve were studied in 10 cadavers with equal sex distribution (5 male and 5 female). Cross-sectional area (CSA) of the pudendal nerve at various sites of entrapment (piriformis, sacrospinous ligament, sacrotuberous ligament, and at Alcock's canal) and trajectory distance of pudendal nerve from various anatomical landmarks (ischial spine, sacral tuberosity, pubic symphysis, and inferior pubic ramus) were measured using digital vernier caliper. The CSA of pudendal nerve was more at piriformis (4.04 mm²) it decreased as the nerve travelled further to Alcock's canal (0.35 mm²). On comparison of the CSA and trajectory distances of the pudendal nerve with sex and sides there was no statistically significant difference. Morphologically, formation variation of pudendal nerve from S3 and S4 roots and trunk variations were also observed. These findings of the present study would help in various surgeries of perineum like nerve transfer, in placement of Richters stitch, transobturator tapes, pudendal nerve block etc.