Noun
crazy bone (plural crazy bones)
- The funny bone; the ulnar nerve in the elbow.
1830, Mrs. John Farrar, The Children's Robinson Crusoe, page 318:I have seen a person in England, who had touched a torpedo; and he said the shock it gave him, was like striking that tender part of the elbow, which we call the crazy bone, very hard indeed;
2008, Thomas S. Purtell, Natural Martial Arts, page 34:My hand was at his elbow, my fingers just at the indentation of his elbow, just about where you bump the nerve point everyone calls the “crazy-bone”.