What is the Funny Bone, and Why Does Hitting It Hurt So Much?

iStock / ljubaphoto
iStock / ljubaphoto

The "funny bone" is neither funny (when you whack it on the edge of a piece of furniture), nor a bone (whether you whack it or not). Where'd the name come from, and why is it so painful?

What it is

The funny bone is actually the ulnar nerve, a nerve that runs from the neck all the way to the hand, where it innervates several muscles in the hand and forearm and ends in two branches that innervate the pinkie and half of the ring finger.

Why it hurts

For most of its length, the ulnar nerve is protected, like rest of the body's nerves, by bones, muscles and/or ligaments. As the nerve passes the elbow, though, it runs through a channel called the cubital tunnel, and here it's protected only by skin and fat, making it vulnerable to bumps. When you hit your funny bone, you're actually hitting the nerve against bone and compressing it. The result is an exhilarating cocktail of numbness, tingling and pain that shoots through the areas where the nerve does its work: down the forearm and hand and into the ring and pinky fingers.

Playing the name game

There are two camps in the debate over how the ulnar nerve got be known as the funny bone. One side says that it's an anatomical pun, because the nerve runs along the humerus, which sounds like "humorous." (Get it?) The other side claims that the nerve got its nickname because of the funny (as in odd) feeling you experience after you hit it.

Things could be worse

When you hit your funny bone, it seems like the worst thing in the world, but imagine experiencing chronic irritation there, like someone banging on your funny bone day and night. It sounds like a method of torture you'd dream up in a revenge fantasy, but it's a very real problem called cubital tunnel syndrome.

Cubital tunnel syndrome occurs when the ulnar nerve is obstructed during its trip along the elbow and gets pinched or squeezed, usually from sleeping with the arm folded up. The result is the same as a quick whack to the funny bone: numbness, pain and a tingling sensation, but it lasts a bit longer. Over time, progressive irritation of the nerve causes the numbness to settle in and stay. Muscle weakness in the forearm and hand can also set in, and the pinkie and ring finger can curl up in a position called the "ulnar claw." The condition can usually be helped with elbow splinting and the correction of aggravating postures, hand therapy or, in extreme cases, surgery that provides more space for the nerve and reduces the amount of pressure on it.

26 Amazing Facts About the Human Body

Mental Floss via YouTube
Mental Floss via YouTube

At some point in your life, you've probably wondered: What is belly button lint, anyway? The answer, according to Mental Floss editor-in-chief Erin McCarthy, is that it's "fibers that rub off of clothing over time." And hairy people are more prone to getting it for a very specific (and kind of gross-sounding) reason. A group of scientists who formed the Belly Button Biodiversity Project in 2011 have also discovered that there's a whole lot of bacteria going on in there.

In this week's all-new edition of The List Show, Erin is sharing 26 amazing facts about the human body, from your philtrum (the dent under your nose) to your feet. You can watch the full episode below.

For more episodes like this one, be sure to subscribe here.

8 Surprising Facts About Your Nose

iStock/AntonioGuillem
iStock/AntonioGuillem

Your nose is more than just a bump on your face—it’s an important part of the respiratory system and affects many other senses, including your taste and hearing. For being something that’s so central to our daily interactions with the world, there’s still a surprising amount to discover about the nose. Here's a bit of what we do know.

1. Your nose can detect billions of different odors.

Although the human nose is weak compared to canine sniffers, our noses can detect 1 trillion smells. Strangely, scientists still aren’t sure exactly how we smell. For decades, researchers thought the olfactory system worked through receptor binding, meaning molecules of different shapes and sizes bonded to specific parts of the nose like puzzle pieces, triggering smell recognition in the brain. But recently, biophysicist Luca Turin has proposed the nose detects smell through quantum vibrations. Turin suggests the frequency at which different molecules vibrate helps the nose identify them as different scents. The theory could explain why molecules of the same shape smell quite differently. Intriguing as it is, this new theory hasn’t been tested enough to be universally accepted.

2. Our big brains might have caused our noses to protrude.

As anyone who’s been to a zoo probably knows, great apes (the closest human ancestors) have flat nasal openings—and researchers found that type of nose is far more effective at inhaling air than the human version. So what’s up with ours? Scientists think the shape might be a by-product of our big brain. The growing cerebellum forced human faces to become smaller, which probably affected the nose as well.

3. Women's noses are more sensitive than men's.

In the battle of the sexes, women’s noses come out on top. When tested for odor detection and identification, women score consistently higher than men. This might have something to do with the size of their olfactory bulb, a structure in the brain that helps humans identify smells. One study found that women have, on average, 43 percent more cells in their olfactory bulb than men do—meaning they can smell more smells.

4. Holding your nose really does help you swallow something distasteful.

Think you like chocolate just because it tastes good? Think again. Smell is responsible for 75 to 95 percent of flavor, which explains why plugging your nose helps you swallow something unappetizing. More recently, chefs and neurologists have teamed up to create meals for cancer patients and others with a diminished sense of smell, such as the elderly. Cooking meals tailored to the smell-less could help stave off depression and improve the appetite without relying on sugar and salt.

5. Surgeons can regrow damaged noses.

When people have cancer or are in an accident, the nose can become infected or even be completely destroyed. But fear not. Plastic surgeons have a way to regrow your nose—on your forehead. Using cartilage from the ribs and tissue expanders that allow the skin to stretch and grow, a new nose can be formed to replace the old one. And while a nose growing out of your forehead looks odd, it's actually one of the best places for a new nose to grow. The forehead's blood vessels can be harnessed to help grow the tissue, and removing the new nose only leaves a small scar [PDF]. Doctors have performed the procedure in the U.S., China, and India.

6. Your nose can sense more than smells.

The nose doesn’t just translate odors in the nasal passage—the tip is also full of nerves that detect pain and temperature. This helps us “smell” non-odor smells. Even people who can no longer smell things with their olfactory system can detect substances like menthol, the minty compound that makes your skin tingle. (Unfortunately, they can’t detect pure scents like vanilla.)

7. About 20,000 liters of air pass through the nose every day.

The average adult breathes around 20,000 liters of air every day, which keeps the nose quite busy. As the first line of defense for the lungs, the nose filters out small particles like pollen and dust. It also adds moisture to the air and warms it so the lungs are saved from any irritation.

8. Anosmia is just one of several smell disorders affecting the nose.

There are plenty of things that can go wrong in your nose. Allergic rhinitis, sinus infections, and broken noses are just a few. But perhaps less well known are disorders that affect the nose’s ability to smell. Anosmia is the complete inability to detect odors and can be caused by illness, aging, radiation, chemical exposure, or even genetics. Equally bizarre are parosmia and phantosmia: The former changes your perception of smells, and the latter creates the perception of smells that don’t exist. Luckily, only 1 or 2 percent of North Americans suffer from any smell disorders.

SECTIONS

arrow
LIVE SMARTER