There are 206 bones in the human body and not a single one of them is the funny bone!
There is nothing funny about the funny bone except its name, which is actually a misnomer. The funny bone is not a bone – it's the ulnar nerve!
We all have experienced that strange feeling after bumping the back of our elbows. You know what I'm talking about... that sharp, tingling, electric shock sensation, which shoots from the elbow into the ring and small fingers. The sensation is confusing because it makes you want to laugh and cry at the same time as you frantically rub your elbow and shake your hand to make it stop.
The ulnar nerve travels from the neck to the ring and small fingers where it controls wrist and hand movements in addition to providing sensation to the ring and small fingers. Along it's course, the ulnar nerve passes behind the elbow where it is not very well protected. In this location, it rests on the humerus bone (arm bone) and is only covered by a thin layer of skin and fatty tissue, leaving the nerve exposed to external stimuli.
When you bump this region of the elbow, you directly hit your ulnar nerve, creating the “funny bone” sensation. You can recreate the same sensation by tapping on the ulnar nerve with your fingers. However, if you apply continuous pressure on the ulnar nerve, such as when leaning your elbow on a hard surface, you can cause ulnar nerve compression with finger tingling and numbness. This is exactly what people with cubital tunnel syndrome experience.
There are several theories about how the funny bone got it's name. Some people believe it was named after the funny sensation that is experienced when bumping the elbow. Others attribute it to the fact that when bumped, the ulnar nerve becomes compressed by the humerus bone, which is pronounced "humorous."
I'll leave it up to you to decide if you feel the funny bone is really all it's cracked up to be.
Dr. Izadi is a hand, wrist, and elbow orthopedic specialist at MD West ONE.