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Why does it tickle when we hit our funny bone?

Asked by: Lexi Brooks
School: St. John the Evangelist, Binghamton
Grade: 6
Teacher: Mrs. Rai
Hobbies/Interests: Playing basketball, attending Binghamton University basketball games and other sporting events.  
Career Interest: I would love to play in the WNBA, but if I don’t make it, than I want to be a State Trooper. I love sports.

Answer from Sree Koneru

Binghamton University Research Associate, CSERC (Clinical Science and Engineering Research Center)

Department: Bioengineering
Research area: Bio Electromagnetics
Interests/hobbies: Wellness, cricket, volleyball, tennis, cooking, video gaming and most outdoor activities

Lexi, that’s a great question! As a kid, I used to bump my funny bone all the time, but could never figure out why it tickled! There are two theories as to why we call it "hitting the funny bone." The first theory is that it’s a pun since the anatomical name for a bone at the elbow is the "humerus," which sounds like "humorous." The other theory simply states that the name originated because of the funny feeling one gets after bumping the elbow.

Although sometimes painful, the tingling sensation we get after bumping our elbow has nothing to do with the bone at all, but a nerve known as the "ulnar" nerve, which runs along our entire arm. Most nerves in the body are protected by muscle and bone, but the ulnar nerve is only protected by skin and fat as it passes through the elbow region. As a result, hitting the elbow area on a surface actually results in this nerve pressing against the bone, which stimulates it and leads to a tingling sensation in the little finger and half of our ring finger, along with part of our arm. While the ulnar nerve connects only this part of our arm to the body’s nervous system, there are other nerves like the radial nerve and medial nerve, which connect the rest of it.

Although the tingling sensation can be fun for a second, imagine if it lasted all day, along with intense pain. This can happen without the elbow mechanically hitting something and occurs in people who overuse their arm, leading to muscle inflammation and pinching of the nerve against bone. This can lead to conditions such as "tennis elbow" or "golfer’s elbow," depending on the type of nerve affected. This can happen to many athletes or even painters, plumbers, carpenters, butchers etc. Stretching can help with such conditions, but at times surgery may be required.

Over thousands of years, our nervous system has evolved to be sensitive to mechanical, chemical, thermal and electrical stimuli from the environment around us. Hitting our funny bone (ulnar nerve), withdrawing our hand from excessive heat or cold, tasting a lemon, getting an electrical shock or just about anything else we do stimulates our nerves. So the next time you touch something with your little finger, remember that it’s doing the same thing as hitting your funny bone, minus the tingling.  

Last Updated: 3/1/17