In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. Aggravation of this nerve is commonly referre to as hitting one's "funny bone." The ulnar nerve is the largest unprotected nerve in the human body (meaning, unprotected by muscle or bone), and the only unprotected nerve that does not serve a sensory function (those nerves specifically meant to perceive changes in the environment, such as nerves in the skin).