caudal vs vertebral column

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. 

vertebral column

noun
  • The series of vertebrae that protect the spinal cord; the spinal column. 

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