In this anomaly the uterus consists of two horns, which open into a single cervical canal. Sometime one of the two uterine horns is underdeveloped and remains in rudimentary condition (due to atrophy of a paramesonephric duct). This condition is called uterus bicornis with a rudimentary horn. The rudimentary horn usually does not communicate with the cavity of the uterus. This leads to complications when puberty arrives and menstruation begins.