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Re: choana [was SOME SVP TIDBITS]
King, Norm wrote
>I had to ask several people, some of whom know a bit of anatomy and are
>involved in our premed and predental programs. They generally never
>heard the term. Our resident herpetologist and chordate phylogenist (is
>that a word?) finally came to the rescue. It turns out there are two
>One is that the choana is the passageway by which animals get air into
>the mouth/throat while keeping the mouth closed. It appeared first among
>sarcopterygians, and sarcopertygians plus tetrapods are "choanates". It
>includes everything from the external nostrils to the internal nostrils
>(nares, if we're just talking about holes through the bone), or from the
>external nostrils to the back of a secondary palate, for animals that
>have one. It is the whole passageway; there is no special name for the
>passage between the primary and secondary palate.
>As you can see, this is not quite synonymous with internal nostril
>The other definition is that it is the same thing as internal nostril.
>Of course, if you have a choana, then you also have an internal nostril,
>and vice versa.
>I suspect that the first definition was the original one. Otherwise, why
>have a separate word? Then, through use (misuse?), it came to also mean
>internal nostril. I'm speculating.
>Anyway, now I feel better. Thank you, Norm.
>From The New Shorter Oxford English Dictionary (page 391)
Choana (pleural -nae) : A funnel shaped openning, specially either of those
connecting the nasal cavities to the pharynx.
Etymology : Greek khoene = funnel.
Same meaning is given also in The Penguin Dictionary of Biology & Oxford
Concise Dictionary of Zoology.
According to the above choana is the naso-pharyngeal openning (internal
naris), not the whole nasal passage.
Black's Medical Dictionary does not mention the term.
Gautam Majumdar firstname.lastname@example.org