middle finger vs ring finger

middle finger

noun
  • The finger between the forefinger and the ring finger 

  • An obscene gesture directed towards another as an insult, made by sticking up the middle finger of a hand. 

  • An insult directed at someone. 

ring finger

noun
  • Finger between middle finger and little finger; the "third finger" (UK) or the "fourth finger" (US), especially of the left hand. (The ring finger is the left hand; a ring finger is either hand.) 

How often have the words middle finger and ring finger occurred in a corpus of books? (source: Google Ngram Viewer )