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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?

By Heather Hatfield
WebMD Feature

Reviewed By Cynthia Haines

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 intoduring 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, Sound Medicine.

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.'"

Mystery solved.

Eye-Popping Information

Let's get one thing straight: "It is very unlikely our eyes will extrude or 'pop out' if we sneeze too forcefully," says Brian Smart, MD, chairman of the Asthma and Allergy Center of the DuPage Medical Group in Illinois.

Well, if the reason we close our eyes when we sneeze isn't to keep them from popping out of our heads, then why bother?

"Similar to the reflex that occurs when your knee kicks after it's hit with a medical hammer, or the way your hand pulls away from something hot when you burn it, closing your eyes when you sneeze is a powerful reflex," says Smart, who is also a spokesman for the American Academy of Allergy, Asthma and Immunology. "You can try and force yourself to keep your eyes open when you sneeze, but it's hard to do."

Another piece of folklore: We sneeze with our eyes closed to keep the stuff we sneeze out from getting in our eyes. Survey says?

"It is also unlikely that the substances we sneeze will get into our eyes, since the substances we sneeze travel some distance," says Smart. "Incidentally, the fact that we sneeze a considerable distance leads me to remind people to always cover their mouths when they sneeze. This will help slow the spread of respiratory disease, and is simply good manners."

Don't forget to say gesundheit.

Reading This Will Make You Yawn

Sometimes, even thinking about yawning will make you yawn. And when the person next to you does it, forget about it -- you'll yawn, too. With all this talk about yawning, in fact, you've probably already yawned.

"A yawn is an instinctive behavior: You don't have to learn to do it, and yawns are even present before birth," says Robert Provine, a professor of psychology and neuroscience at the University of Maryland, Baltimore County.

Is the myth that yawns are actually contagious true?

"When one person in a group yawns, over half of the people in the group will yawn within five minutes, and the rest will at least be tempted to yawn," says Provine, who has been researching yawning for more than 20 years. "What is surprising is that virtually anything having to do with yawning triggers a contagious reaction."

Provine explains that while yawning is highly contagious, so are other human behaviors, like laughter, and this reaction is actually very normal -- and ancient.

"When you see someone else yawn, you don't think to yourself, 'Well, I'll yawn, too," says Provine. "It just happens -- it's instinctive, and it's a very primal aspect of human behavior that goes back to ancient herd mentality."

Mysteries, Solved

Now that you know why yawns are contagious and why your funny bone should actually be called a painful nerve, here are other medical mysteries, unraveled:

Why do you lose your sense of taste when your nose is stuffy? According to the American Academy of Family Physicians web site, the flavor of food involves both taste and smell. If your nose is stuffy, you are left to rely on only half of the flavor equation: just your taste buds, and those buds can only differentiate between four or five different molecules, while the nose can distinguish between about 10,000. In short, your nose knows.

Is brain freeze really your brain gone cold? In an editorial in the British Medical Journal, author Joseph Hulihan describes ice cream headache, commonly known as brain freeze, as a pain that begins a few seconds after eating cold foods or beverages, peaks in 30-60 seconds, and is located in the mid frontal area of the brain. Why does it occur? It's been studied as an example of referred pain, or pain that starts in one part of the body, but is felt in another. In the case of brain freeze, the pain originates in the mouth and is referred through the tongue to the brain. The good news is that brain freeze isn't deadly, and no treatment is usually required. In fact, writes Hulihan, "Ice cream abstinence is not indicated."

Why can't you get the Disney ditty "It's a Small World" out of your head? According to a University of Cincinnati news release, marketing professor James J. Kellaris, PhD, explains that this song is a leading earworm -- a tune that gets stuck in your head and won't let go. Earworms are experienced by more than 97% of the population, according to the release, and drive a person crazy from a few hours to over a week. Why do earworms strike? Overexposure to music can play a role, as can stress, fatigue, or pressure. So relax, and let earworms find someone else to feed on.

Sleep Tight

Now that you know the answers to some of life's medical mysteries, sleep tight, and don't let the bed bugs bite.

(One last mystery solved: Bed bugs aren't only the stuff of childhood rhymes: they're real, and they do bite. Think you have bed bugs? They're 1/4 inch long, reddish-brown, and are usually detected by welts and irritations on the skin that aren't there when you go to bed but are when you wake up, according to the University of Kentucky Entomology web site. Solution? Call pest control.)

Originally published Oct. 6, 2003.

Medically updated Sept. 21, 2004.




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