canon bone vs shankbone

canon bone

noun
  • The shankbone, or great bone above the fetlock, in the fore and hind legs of the horse and allied animals, corresponding to the middle metacarpal or metatarsal bone of most mammals. 

shankbone

noun
  • Synonym of canon bone 

How often have the words canon bone and shankbone occurred in a corpus of books? (source: Google Ngram Viewer )