Hoan's

Nasal passages (choanal openings, choanae, leg canals; lat. Choanae) - two narrow canals or openings that connect the nasal cavity with the pharynx and open in its posterior wall at the level of the nasopharyngeal vault: the paired nasopharyngeal (respiratory) nostril, or the smaller nasal canal , on each side of the pharynx. In humans, a pair of choanae are located between the base of the uvula and the mucous membrane of the lateral wall of the nasopharynx at the level of the bifurcation of the hyoid bone in the middle part of the palate. In accordance with the international nomenclature code NOS (ICD-10), the disease (“bird’s head”) “choanal atresia” is included in group Q38 “Other congenital anomalies of the external nose.”