caudal vs occiput

caudal

noun
  • A caudal vertebra. 

adj
  • Toward the tail end (hind end) of the body; in bipeds such as humans, this direction corresponds to inferior. 

  • Pertaining to the tail or posterior or hind part of a body. 

occiput

noun
  • The back part of the head or skull. 

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