A Cadaveric Variation in the Posterior Cutaneous Nerve of the Thigh: Embryological Insights and Clinical Implications

Abstract

Background: The posterior cutaneous nerve of the thigh (PCNT), also known as the posterior femoral cutaneous nerve, is a sensory branch of the sacral roots derived from S1–S3 nerve roots. It supplies the gluteal, perineal, and posterior thigh regions. Anatomical variations in the origin or course are uncommon but clinically significant, as they may impact outcomes in gluteal and posterior thigh procedures such as hip replacements, hamstring repairs, and nerve blocks. Case Description: During the dissection of a well-preserved 63-year-old male cadaver, a unique variation of the PCNT was found on the right side. The nerve exhibited a dual origin from the sciatic as well as pudendal roots and was pierced by the inferior gluteal vessels below the piriformis muscle and contributed fibers to the sciatic nerve. Several oblique communicating fibers were also observed between S1, S2, and S3. The left side showed normal anatomy. Methods: Dissection of the gluteal region was conducted as per the steps mentioned in Cunningham’s manual of dissection. Morphometric measurements were obtained with digital calipers, referenced from the inferior border of the piriformis muscle. Conclusion: Anatomical variations may have significant clinical consequences, particularly during surgical or anaesthetic interventions in the gluteal or thigh areas. This unique variation, pierced by the inferior gluteal vessels, may predispose the PCNT to vascular compression or iatrogenic injury. This could result in neuralgia, hypoesthesia, or sensory loss in its distribution areas. Embryological factors such as anomalies in neural crest cell migration or neurotrophic signaling may contribute to such variations. Understanding such variants is crucial for surgeons to minimize complications during regional procedures.