Choana

Near-synonyms: infundibulum, pelvis, cornu

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.)

The bony rim of the posterior choana is located by passing the 4-mm microdebrider blade through the posterior ethmoids and into the nasopharynx. The tip of the microdebrider blade is pushed against the mucosa just above the bony choanae on the anterior face of the sphenoid.