Normal anatomic relationships in prepubescent female external genitalia

Female congenital abnormalities and concomitant ambiguous genitalia constitute the primary reason for female genital reconstruction, however, objective data describing normal female anatomy is lacking. The aim of this study is to describe the normal anatomical relationships and size of the external genital structures in prepubescent females.

Data were collected prospectively from consecutive Tanner stage 1 females undergoing surgery unrelated to the genitalia. Recorded measurements included: clitoris length and width, length from clitoris to anus, clitoris to urethra, clitoris to posterior labia majora, mucosa behind vagina or posterior fourchette, and radius to labia minora at vagina. Patients were stratified by age into four age groups: <2 years, 2-5 years, 5-11 years and >11 years.

Fifty-six patients met inclusion criteria. Clitoral width was similar in all age groups. The regression plots for the remaining measurements modeled on age all show a significant linear growth distribution.

The average clitoral width was 3.8 mm, which remained constant between age groups. Clitoral length, length from clitoris to anus, clitoris to posterior labia majora, clitoris to urethra and posterior fourchette length increased across age groups. This study provides insight into the dimensions of normal external genitalia in tanner stage 1 females.