cervix vs occiput

cervix

noun
  • The neck 

  • The lower, narrow portion of the uterus where it joins with the top end of the vagina. 

  • The necklike portion of any part, as of the womb. 

occiput

noun
  • The back part of the head or skull. 

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