PVE classification of persistent Urogenital sinus

quote from "Pediatric Surgery (Springer Surgery Atlas)" by Prem Puri, Michael E. Höllwarth -

"Rink et al. described the “PVE” classification, in which the length and width of the phallus (P) is measured in centimeters, the location of the vaginal confluence (V) is recorded in centimeters from the bladder neck and from the UGS opening, and the degree of masculinization of the external genitalia (E) is estimated with a Prader number of 1–5."