fauces vs oral cavity

fauces

noun
  • The narrow passage from the mouth to the pharynx, situated between the soft palate and the base of the tongue. 

  • That portion of the interior of a spiral shell which can be seen by looking into the aperture. 

  • The throat of a calyx, corolla, etc. 

oral cavity

noun
  • The cavity of the mouth, especially the part of the mouth behind the gums and teeth that is bounded above by the hard and soft palates and below by the tongue and by the mucous membrane connecting it with the inner part of the mandible. 

  • The hollow on the lower surface of the head from which the proboscis protrudes. 

How often have the words fauces and oral cavity occurred in a corpus of books? (source: Google Ngram Viewer )