fistula vs inner tube

fistula

noun
  • A tube, a pipe, or a hole. 

  • An abnormal connection or passageway between organs or vessels that normally do not connect. 

  • The tube through which the wine of the Eucharist was once sucked from the chalice in certain ceremonies (such as papal Masses). 

inner tube

noun
  • Synonym of swim ring 

  • An inflatable rubber tube inserted into the casing of a pneumatic tyre/tire. 

How often have the words fistula and inner tube occurred in a corpus of books? (source: Google Ngram Viewer )