Labiaplasty - Surgical Anatomy of The Vulva

Surgical Anatomy of The Vulva

The vulvo-vaginal complex

The external genitalia of a woman are collectively denoted the vulvo-vaginal complex, which comprises the labia majora, the labia minora, the clitoris, the urethra, and the vagina. The fatty labia majora (the large outer lips) extend from the mons pubis to the rectum. The vascularized labia minora (the small inner lips) are within the labia majora; however, in some women, the minor lips are short and thin and hidden by the labia majora; and in some women, the labia minora are longer, thicker, and wider, and extend beyond the labia majora.

Composition

The labia minora consist of two (2) connective folds of flesh that contain some adipose tissue; at the front and upper portions of the Vulva (vulva), the labia minora divide into two parts. The first part passes over the clitoris, and forms the prepuce of the clitoris (clitoral hood); the second part of the labia minora joins beneath the clitoris and forms the fourchette (labial frenulum), a transverse fold of tissue that occasionally unites the labia minora to the labia majora at their posterior extensions. The skin and the mucosa of the labia minora are rich in sebaceous glands and nerve endings, thus the labia are very sensitive to the touch. These folds of vulvo-vaginal skin have a core of connective, erectile tissue (analogous to the corpus spongiosum penis), and are covered by stratified, squamous epithelium — thus, the labia minora moisten and swell with extracellular fluid during sexual arousal. Furthermore, during urination, the labia minora function to direct the urine stream away from the vulva.

Labial anatomic variation

The size, the shape, and the skin coloration of the labia minora vary according to the woman, thus, like most paired structures of the human body, the labia are not anatomically symmetrical — one labium minus (minor lip) usually is greater (longer, wider, thicker) than its pair — yet the asymmetry usually is not notable. Moreover, the length and the width of the labia minora determine if they protrude from, or are hidden by, the labia majora. Further increases in the sizes of the labia (majora and minora) occur when the woman is sexually aroused — in preparation for coitus — wherein the labia become engorged with blood and increase the labial diameters two-to-three times.

Labial hypertrophy can be caused by the mechanical stresses inherent to the cultural practice of genital piercing, the bearing of relatively heavy-weight metal ornaments attached through the perforated labium or labia, which is medically notable because bearing weight is not a usual anatomic function of the labia minora. Furthermore, oversized labia minora can also be a genetically inherited anatomical feature of the woman’s vulva. The plastic surgery study Labiaplasty and Labia minora Reduction (2008) reported the occurrence of labia minora of like sizes (length, width, girth) in identical twin sisters treated for labial hypertrophy, which might indicate a genetic predisposition to developing oversized labia minora.

Measures of the vulva

Because there is no formal, medical definition of labial hypertrophy (length, width, girth), nor a standardized method for grading the degree of hypertrophy present, the plastic surgeon and the woman determine the applicability of labial reduction to her case without a fixed anatomic reference. To the end of providing such a medical reference, the morphologic study Female Genital Appearance: ‘Normality’ Unfolds (2005) reported the range of anatomic variations of the vulvo-vaginal complex of a 50-woman cohort (18–50 y/o, mean age 35.6 yrs.); the statistical variations of the vulva are: