[Congenital fistula of the lower lip. Apropos of 2 cases].

Two children with bilateral congenital fistulae of the lower lip were treated by excision maintaining the fibers of the orbicular muscle. This condition is a rare, hereditary trait often associated with labial and palatine fissures. The etiology is different than other fistulae since the localization does not involve zones of junction between facial buds. On the basis of the embryology reported in the literature, it would appear that a morphogenic factor related to the position of the upper incisives might be involved.