innards vs marrowbone

innards

noun
  • The internal organs of a human or animal; especially viscera, intestines. 

  • The inner workings of something; the insides or guts. 

marrowbone

noun
  • A bone containing edible marrow. 

  • The shins or knees, chiefly in references to kneeling. 

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