Medical Mysteries, She Wrote
Have you ever wondered why it hurts when you hit your funny bone? Or why your eyes close when you sneeze? WebMD has the answers to these and other perpetually perplexing medical mysteries.
Why is hitting your funny bone anything but funny? Does
sneezing really make your eyes pop out of your head? And why, no matter how
hard you try, can't you stop from yawning when the person next to you yawns?
Here are some of life's little medical mysteries -- solved.
Hitting Your Funny Bone
The funny thing is, the funny bone isn't a bone at all, but a
nerve, and hitting it is anything but funny -- in fact, it's painful.
The nerve that is referred to as the funny bone is the ulnar
nerve, which extends down the arm, across the elbow, and into the hand. It
provides sensation to the little and ring fingers and activates many of the
muscles in the hand, according to the American Association of Orthopaedic
Surgeons web site.
"The ulnar nerve happens to be very superficially placed in
the back of your elbow," says Ed Toriello, MD, a fellow of the American
Academy of Orthopaedic Surgeons. "At this spot, it lies directly
under the skin and runs in a hard, bony
groove on its way to your hand."
Why is hitting it guaranteed to make you cringe with pain,
rather than laugh, as its nickname suggests?
"Nerves are very temperamental and sensitive
structures," says Toriello, who is an orthopaedic surgeon in private
practice in New York. "For this reason, nerves generally course deep in
muscles, where they are protected from direct contact with the things we bump
into during our normal course of living. The ulnar nerve at the
elbow is an exception, because it lies in a spot that is very vulnerable and
protected only by a thin layer of skin."
When you bump the back of your elbow directly over the ulnar
nerve, it's caught between what you hit and the bony groove, explains Toriello.
A painful electrical impulse is discharged from the nerve, which runs through
the arm and into the little and ring fingers.
So shouldn't it be called the painful nerve, instead of the
funny bone? One theory is that the name funny bone is a pun on the Latin word
humerus, which describes the part of the arm between the shoulder and
the elbow, according to the Indiana University School of Medicine web site,
Another theory is that the "funny" in funny bone means
strange rather than ha-ha.
"My suspicion is that the first person who experienced this
sensation when he or she struck their elbow did not find it fun, but rather
found it an odd sensation since it didn't seem to happen when they bumped other
parts of their body," says Toriello. "So I think 'funny' in this
context really means 'odd or 'strange.'"