Surgical and anatomical landmarks for the perineal branch of the posterior femoral cutaneous nerve: implications in perineal pain syndromes. Laboratory investigation.

OBJECT: The perineal branch of the posterior femoral cutaneous nerve (PBPFCN) has received little attention in the literature. Because perineal pain syndromes can be disabling and pudendal nerve surgical decompression/block is often not efficacious, an anatomical study of this cutaneous nerve of the perineum seemed warranted.

METHODS: The authors dissected 20 adult cadavers (40 sides) to identify the branching pattern and landmarks for the PBPFCN.

RESULTS: This branch arose directly from the posterior femoral cutaneous nerve in 55% of sides and from the inferior cluneal nerve in 30% of sides. It was absent in 15% of sides. On average, the nerve coursed 4 cm inferior to the termination of the sacrotuberous ligament onto the ischial tuberosity. No PBPFCN was found to pierce the sacrotuberous ligament. The PBPFCN provided 2-3 branches to the medial thigh that continued on to the scrotum and labia major. In general, 2 small ascending branches were identified. In males, one ascending branch traveled inferior to the corpora cavernosum and anterior to the spermatic cord to cross the midline. The other ascending branch traveled to skin at the junction of the perineum and adductor tendon. A single descending branch, approximately 2 mm in diameter, traveled to the inferior scrotum anterior to the testicle in the male specimens and the lower labia majora in the female specimens. Communications between the PBPFCN and the perineal branch of the pudendal nerve were common.

CONCLUSIONS: Entrapment of the PBPFCN may be the cause of some forms of the perineal pain syndrome. Specific knowledge of the PBPFCN may assist surgeons in releasing and anesthetizing this cutaneous nerve of the perineum.