The funny bone, or crazy bone, is a location on the humerus (the large bone of the upper arm), near the elbow. There the ulnar nerve, one of the three long nerves of the arm, crosses the surface of the bone before dividing to go to various parts of the forearm and hand. The exposed location of the nerve at this point makes it easily hit. The peculiar tingling pain that follows accounts for the term "funny bone" or "crazy bone."