Navicular fossa is a part of the human reproductive organs, male and female have, as follows: 1, the male urethra by the genital diaphragm is divided into front and rear parts, the front urethra is from the urethral orifice to the bulb so far, roughly 15cm. outside is the urethral spongiosum, attached to two penile spongy structures, the urethra at the head of the penis to expand the urethra known as urethral navicular fossa; 2, the female vagina mouth and vaginal tract between a shallow fossa, known as the navicular fossa This is the vestibular fossa of the vagina. In unmarried or infertile women is more obvious, postpartum by the impact of pregnancy and childbirth, navicular fossa will disappear.