The peritoneo-vaginal duct is an evagination of the peritoneum that attaches to the testis and becomes obliterated as the testis descends into the scrotum. An indirect inguinal hernia occurs when the normal obliteration of the vaginal process does not occur.
In the female, if the vaginal process remains patent, it extends into the labia majora. When luminal obliteration does not occur, there is a sac through which abdominal contents can herniate through the inguinal canal*.
A child with an inguinal hernia usually presents with an obvious bulge in the inguinal canal or within the scrotum. Parents usually provide a history of a visible bulge, commonly intermittent, in the inguino-scrotal region in boys and in the inguino-labial region in girls*.
There is usually no pain associated with a simple inguinal hernia. The bulge commonly occurs after crying or straining and resolves during the night while the baby sleeps or feeds*.