choana

1. (anatomy, zootomy) A pair of apertures towards the back of the nasal cavity, opening into the nasopharynx.Examples: "The choanal glands of caecilians open at the margin of the choanae, whereas those of salamanders open deep within the choanae at the margin of the olfactory epithelium."; "Zuckerkandl (1893) gives far and away the greatest measurements for the choanae; Hopmann (1895) reported that in man the choana has a mean height of 27 mm, and a mean width of 13 mm (Merkel, 1896); in women it measures 25 x 12mm. These values agree closely with our findings."; "Inside of this area it is possible to identify clearly two parallel echonegative zones, which belong to the nasal cavities (choanas) and are placed on both sides of a medial structure, considerably echogenic, which corresponds to nasal bridge (Fig. 2.12.)"Synonyms: internal nostril, posterior naris, posterior nasal aperture