index finger vs toenail

index finger

noun
  • the forefinger 

toenail

noun
  • The thin, horny, transparent plate covering the upper surface of the end of a toe. 

verb
  • To fasten two pieces of lumber together by applying nails or screws into both boards at an angle. 

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