Terminal innervation of the male genitalia, cutaneous sensory receptors of the male foreskin.

PURPOSE: Understanding the types of sensory nerve termini within the glabrous skin of the human male foreskin could throw light on surgical outcomes and therapeutic possibilities for the future. Various receptor types sense changes in temperature, position, pressure, pain, light touch, itch, burning and pleasurable sexual sensations. Similarities and differences in innervation characteristics and density might become apparent when the glans penis is compared with homologous structures in the female genitalia. The aim of this study is to document the presence and characteristics of cutaneous sensory receptors in the human penile foreskin using a histopathological study of the nerve termini to achieve a more complete understanding of sensory experiences. METHODS: Foreskin samples were obtained from ten boys (aged 1-9 years) who had undergone circumcision. Informed consent was obtained from the parent/legal guardian. The samples were examined after modified Bielschowsky silver impregnation of neural tissue, and immunocytochemistry against gene protein product (PGP) 9.5 and neuron-specific enolase (NSE). RESULTS: PGP 9.5 appeared to be the most sensitive neural marker. Free nerve endings were identified in the papillary dermis visualized as thin fibers, mostly varicose, with either branched or single processes, either straight or bent. Two types of sensory corpuscle were identified: capsulated and non-capsulated. Meissner-like corpuscles were located in the papillary dermis. Capsulated corpuscles resembled typical Pacinian corpuscles, comprising a single central axon surrounded by non-neural periaxonic cells and lamellae. The capsulated corpuscles were strongly positive for PGP 9.5 and NSE. CONCLUSIONS: Free nerve endings, Meissner's corpuscles and Pacinian corpuscles are present in the human male foreskin and exhibit characteristic staining patterns.

Self-assessment of anatomy, sexual sensitivity, and function of the labia and vagina.

Patient perceptions of genital esthetics are motivating requests for plastic surgeries that could change sexual sensitivity. There is little information about the sensitivities of labial and introital sites. The aim of this study is to assess the relationship between sexual sensitivity and self-reported sizes of labial and introital sites. Sixty-two healthy, sexually active, adult women (mean age 37.9, range 21-60) with no history of genital or vaginal surgery gave written consent to participate in this study. A modified version of Self-Assessment of Genital Anatomy and Sexual Function (L-SAGASF-F) was used to assess labial and introital size. Site-specific sensation was rated on Likert scales of 1-5. Anatomical locations were compared for ratings. Of 62 responders, 84% (52) described their labia as "average-sized," 11% (7) described their labia minora and 13% (8) their labia majora as "large", and 3% (2) and 5% (3) as "small". Sexual pleasure ratings were "moderate" (median value: 3.0 for external genitalia and vaginal lumen) or "strong" (median value: 4.0 for the interior vagina). Significantly higher rankings related to the vaginal opening (P=0.007). Orgasm intensity for stimulation of the external genitalia progressively increased toward the vaginal opening, from 1.0 to 3.0 (P=0.001); vaginal ratings showed a similar progression, from 2.0 at the external luminal margin to 3.0 in the deep interior (P<0.0001). Orgasm effort scores were intermediate (median: 3.0), uniform throughout the external and internal areas (P=0.626). Ratings for labial and introital sensitivity, regardless of self-reported size, were very similar to those at other genital sites for sexual pleasure. Surgical excision of labial and introital structures could modify sexual sensation.