Genital anatomy in non-abused preschool girls

To describe the normal variations in genital anatomy in preschool girls selected for non-abuse.

A total of 2731 girls aged 5 or 6 y were invited to take part in the study; 195 girls were recruited. Inclusion was based on self-selection, whereby parents who did not suspect any occurrence of sexual abuse of their children gave informed consent to participate. Several steps were taken 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 using a separation and traction technique, and in the prone knee-chest position.

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 feature that could be difficult to distinguish from attenuation of the posterior hymen. A gaping hymenal orifice, previously suggested to be a supportive sign of sexual abuse, was fairly frequently found and significantly associated with a large horizontal hymenal diameter.

To distinguish between girls with outward folding of the posterior hymen and those 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, these measurements should be used with caution in sexual abuse evaluations.