funny bone

1. A point on the elbow where the ulnar nerve runs close to the surface and produces a sharp tingling sensation if knocked against the bone.
2. A sense of humor.

Usually applied to the projection, the olecranon, at the back of the elbow, which is the upper end of the ulna, one of the two forearm bones. On the inner side of this is a smaller protuberance, the medial epicondyle of the humerus — the bone of the upper arm. The ulnar nerve runs in a groove on the back of the epicondyle, between this and the olecranon. The nerve can be felt and rolled under the fingers, most easily when the elbow is at a right angle, and because it is near the surface it can be painfully tweaked if the inner side of the elbow hits a hard surface. The sensation is funny only in the sense of peculiar. (Tempting though it be, there is apparently no pun intended to link it to the humerus — whose name is Latin for shoulder, referring to its upper end.)

— Stuart Judge

See elbow; skeleton.

1.  A point on the elbow where the ulnar nerve runs close to the surface and produces a sharp tingling sensation when knocked against the bone. For example, Ouch! I just banged my funny bone. The expression is a pun on humerus (pronounced the same as humorous), the Latin name for the long bone of the arm. [Early 1800s]
2.  A sense of humor, as in That comedian really tickles my funny bone. This expression is derived from def. 1.

The funny bone is not a bone but part of the ulnar nerve located at the the back of the elbow. A bump in this area can cause a tingling sensation or it can make the forearm feel temporarily numb.

The funny bone is not really a bone. It is actually a big nerve that runs through your forearm to the back of your elbow. When you hit that nerve in your elbow on something hard, it really hurts and sometimes causes tingling or temporary numbness in your arm. What's so funny about that? The funny bone got its name from the bone located above it, the humerus (sounds like "humorous") bone in the upper arm.