Genital anatomy in non-abused preschool girls

Aim: To describe the normal variation in genital anatomy in preschool girls selected for non-abuse. Methods: A letter of invitation was sent to 2731 five or six years old girls, and 195 girls were recruited. Inclusion was based on self-selection, whereby parents who did not suspect any occurrence of sexual abuse of their child gave informed consent to participate. Several steps were undertaken to exclude abused girls and girls with previous accidental genital injuries. The genital examination, using a colposcope and a camera, was performed in supine position with separation and traction technique, and in the prone knee-chest position. Results: A number of genital anatomical features and hymenal measurements were described and found consistent with previous studies. An important finding was outward folding of the posterior hymenal rim in many girls, a finding that could be difficult to distinguish from attenuation of the posterior hymen. The finding of a gaping hymenal orifice, previously suggested to be a supportive sign of sexual abuse, was fairly frequent and significantly associated with a large horizontal hymenal diameter. Conclusion: To distinguish between girls with outward folding of the posterior hymen and girls with attenuated hymens, we recommend the use of the saline irrigation method. Even though normative hymenal measurement data now exist from a reasonable number of girls, such measurements should be used with caution in sexual abuse evaluations.