Choanal Atresia

**Definition:** A congenital abnormality that is characterized by a blocked CHOANAE, the opening between the nose and the NASOPHARYNX. Blockage can be unilateral or bilateral; bony or membranous.

**Tree numbers:** - C08.460.171 - C08.695.271 - C09.603.171 - C16.131.740.271

**Synonyms:** - Atresia, Choanal