ulna vs upper arm

ulna

noun
  • The bone of the forearm that extends from the elbow to the wrist on the side opposite to the thumb, corresponding to the fibula of the hind limb. Also, the corresponding bone in the forelimb of any vertebrate. 

upper arm

noun
  • The section of an arm from the elbow to the shoulder. 

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