A prospective study examining the anatomic distribution of nerve density in the human vagina

Abstract

Introduction: Women possess sufficient vaginal innervation such that tactile stimulation of the vagina can lead to orgasm. However, there are few anatomic studies that have characterized the distribution of nerves throughout the human vagina.

Aim: The aim of this prospective study was to better characterize the anatomic distribution of nerves in the adult human vagina. A secondary aim was to assess whether vaginal innervation correlates with the subject's demographic information and sexual function.

Methods: Full-thickness biopsies of anterior and posterior vagina (proximal and distal), cuff, and cervix were taken during surgery in a standardized manner. Specimens were prepared with hematoxylin and eosin, and S100 protein immunoperoxidase. The total number of nerves in each specimen was quantified. Enrolled patients completed a validated sexual function questionnaire (Female Sexual Function Index, FSFI) preoperatively.

Main outcome measures: A description of vaginal innervation by location and an assessment of vaginal innervation in association with the subject's demographic information and sexual function.

Results: Twenty-one patients completed this study, yielding 110 biopsy specimens. Vaginal innervation was somewhat regular, with no site consistently demonstrating the highest nerve density. Nerves were located throughout the vagina, including apex and cervix. No significant differences were noted in vaginal innervation based on various demographic factors, including age, vaginal maturation index, stage of prolapse, number of vaginal deliveries, or previous hysterectomy. There were no correlations between vaginal nerve quantity and FSFI domain and overall scores. Fifty-seven percent of the subjects had female sexual dysfunction; when compared to those without dysfunction, there were no significant differences in total or site-specific nerves.

Conclusions: In a prospective study, vaginal nerves were located regularly throughout the anterior and posterior vagina, proximally and distally, including apex and cervix. There was no vaginal location with increased nerve density. Vaginal innervation was not associated with demographic information or sexual function.