choanal atresia /kō″ənəl/ [Gk, choane, funnel, a + tresis, not hole] , a congenital anomaly in which a bony or membranous occlusion blocks the passageway between the nose and pharynx. The condition, which is caused by the failure of the nasopharyngeal septum to rupture during embryonic development, can result in serious ventilation problems in the neonate; therefore providing an oral airway or endotracheal intubation may be necessary. The defect is usually repaired surgically shortly after birth.
