descending part of facial canal

de·scend·ing part of fa·cial ca·nal

second portion of the facial canal, after the horizontal parts, beginning at the posterior end of the lateral crus where the canal begins to descend. It runs vertically downward, ending at the stylomastoid foramen. Anteriorly, the descending part of the facial canal communicates with the tympanic cavity through the canaliculus for the nerve to the stapedius muscle and the posterior canaliculus of the chorda tympani.
See also: facial canal.
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