The “funny bone” is not actually a bone, but rather a common term for the ulnar nerve, which runs down the back of the elbow. It rests against the humerus — the long bone of your upper arm — and is not well-protected by muscle. When you hit this spot, you’re bumping the ulnar nerve against the humerus, causing a sharp, tingling, or electric sensation that radiates down to your ring and pinky fingers. While the feeling is intense, it’s harmless. The name “funny bone" is a pun on the word humerus/humorous.
