Elbow Questions

Question: Why does it hurt so much to hit your elbow, but not at all to pinch the skin there?

Answer: I think the first thing to establish here is that when you bonk your funny bone on the table in the mad dash for the last slice of pizza, it hurts because you’re hitting your ulnar nerve, not necessarily because you’re hitting a bone.

“When you hit, you actually hit the nerve and so it’s hard to pinch because it’s sort of running in a groove,” said Vanessa Williams, a lecturer on human anatomy and physiology in the department of cell biology. “When you pinch you get skin and subcutaneous tissue, not the nerve itself. You don’t get a lot of nerves in the subcutaneous tissue.”

Hold your arm out in front of you, slightly bent. If you feel the point of your elbow, and then move your fingers slightly towards the inside of your arm, you’ll feel the slight groove Dr. Williams mentioned.

That’s the cubital tunnel, and your ulnar nerve runs from your neck, down trough the tunnel and into your ring and pinky fingers.

In the rest of your arm, the nerve runs along bone and is protected from clumsy flailing by the muscle of your arm and forearm. But your elbow is actually just skin, bone and this nerve so when you hit it, the nerve gets compressed between your bone and that hard surface.

And no matter what all your friends told you in middle school, there is no technical term for the skin of your elbow.

Anything you learned, as a pre-teen was just silly slang meant to embarrass and confuse you — just like the rest of middle school social life.

I'm not sure why the elbow is sometimes called the funny bone. Maybe because of the humerus, which is the bone in your upper arm, or maybe because people laugh at you because of the noise you make when you hit your elbow.

Editor's note: To submit a question to She Blinded Me with Science, send it to The Red & Black's science beat reporter, Jeanette Kazmierczak, @sciencekaz.

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