Neurovascular anatomy of the penis and pelvis in Thai males: applications to male-to-female and pelvic surgeries.

OBJECTIVE To determine the neurovascular profiles in the pelvis and penis for applying to sex reassignment surgery. MATERIAL AND METHOD Dissection of the pelvis and penile shaft was performed in 12 soft-preserved and 32 fresh adult male cadavers respectively. The neurovascular structures were located and documented, and the distances between anatomical landmarks were measured. Thirty-two specimens from the glans penis were obtained for immunohistochemical analysis to analyze its innervation and blood supply. RESULTS Several anatomical variations of penile arterial supply were found. They are the presence of the accessory pudendal artery, multiple cavernous and bulbourethral arteries. The unilateral dorsal artery was observed in 10 of 32 cadavers, predominantly on the left. From the root to the neck of the penis, the dorsal nerves were divided into two groups. The first group of fibers innervating the glans coursed along the dorsolateral surface of the shaft and pierced the entire area of the corona. The other group diverged to distribute throughout the lateral surface to innervate the lateral and ventral portions. The mean distance between the left and right medial main branches that terminated in the glans was 1.18 cm. Immunohistochemical analysis revealed that the main nerves, after entering the glans, divided into terminal branches that concentrated around urethra. A mean distance from the main nerves to the epithelium was 0.71 cm. CONCLUSION This detailed anatomy in the pelvis and along the penis should provide a valuable guide for sex reassignment surgery and intrapelvic operations.