marrowbone vs medulla

marrowbone

noun
  • A bone containing edible marrow. 

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

medulla

noun
  • The inner substance of various organs and structures, especially the marrow of bones. 

  • The medulla oblongata. 

  • The soft inner part of something, especially the pith of a fruit. 

  • The internal tissue of a plant. 

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