Congenital Malformation: Choanal Atresia

The choana is the posterior nasal aperture. It is the opening between the nasal cavity and the nasopharynx. It is not actually a structure but rather a space bounded anteriorly and inferiorly by the horizontal plate of palatine bone, superiorly and posteriorly by the sphenoid bone, medially by the nasal septum and laterally by the medial pterygoid plates.