Anatomy, histology, and nerve density of clitoris and associated structures: clinical applications to vulvar surgery.

Background A precise understanding of structures comprising the female external genitalia is essential in obstetric and gynecologic practice. Objective To further characterize the anatomy, histology, and nerve density of the clitoris and associated structures, and to provide clinical correlations to vulvar surgery. Materials and Methods Unembalmed female cadavers were examined. The length and width of the body, glans, and crura of the clitoris were measured. Distances from the glans to the urethra and from the dorsal surface of the clitoral body to the mid pubic arch were recorded. The path of the dorsal nerve of the clitoris was examined, and the nerve width was measured as it emerged from the lateral surface of crura and at the distal clitoral body. Distances from where the dorsal nerve emerged from the perineal membrane to the posterior surface of the membrane and to mid pubic arch were measured. Connective tissue layers associated with the clitoris were examined. Tissue was harvested from additional unembalmed cadavers, and nerve density of the labia minora, glans, and clitoral body were analyzed. Histological examination was performed on vulvar structures to clarify tissue composition. Descriptive statistics were used for data analyses. Results A total of 27 cadavers (aged 48–96 years) were examined, 22 grossly and 5 histologically. The median length and width of clitoral body were 29 mm (range, 13–59 mm) and 9 mm (range, 5–14 mm), respectively. The glans was 8 mm (range, 5–12 mm) long and 4 mm (range, 3–10 mm) wide. The length of the crura was 50 mm (range, 25–68 mm), and the width at the anterior portion was 9 mm (range, 2–13 mm). The closest distance from the glans to the urethra was 25 mm (range, 14–37 mm) and from the clitoral body to the mid pubic arch was 29 mm (range, 14–46 mm). The widths of the dorsal nerve at the lateral crura and at the distal clitoral body were 3 mm (range, 2–4 mm) and 1 mm (range, 1–2 mm), respectively. The distance from the dorsal nerve as it emerged from the perineal membrane to the mid pubic arch was 34 mm (range, 20–48 mm) and to the posterior surface of the membrane was 20 mm (range, 8–31 mm). The dorsal nerve and artery of the clitoris coursed adjacent to the medial surface of the inferior pubic ramus surrounded by a dense fibrous capsule adherent to the periosteum. The nerve and artery then coursed deep to dense connective tissue layers, which were contiguous with the suspensory ligament and fascia of the clitoris. Histologic examination revealed the presence of erectile tissue in the clitoral body, crura, and vestibular bulbs, but such tissue was absent in the glans and labia minora. Nerve density analysis revealed statistically significant greater density in the dorsal compared with ventral half of the clitoral body. Although not statistically significant, there was increased nerve density in the distal compared to the proximal half of the labia minora. Conclusion Precise knowledge of clitoral anatomy and associated neurovascular structures is essential to safely complete partial vulvectomies, clitoral and vulvar reconstructive procedures, anti-incontinence surgeries, and repair of obstetric lacerations. Understanding the range of anatomic variations and awareness of the areas of increased nerve density is important during counseling and surgical planning. Although the dorsal nerve of the clitoris courses deep to dense connective tissue layers, inadvertent injury may occur in the setting of deep dissection or suture placement. The dorsal nerve seems most vulnerable with surgical entry or lacerations that extend from the midline of the prepuce to the inferior pubic rami.