Why does your funny bone hurt when you hit it?

ScienceAnatomyBiology
Written By Caitlin Olson
 

The short answer

When you hit your funny bone at the right angle, you are hitting the ulnar nerve, one of the three primary nerves in your arm. The pain you’re feeling is the pain of the actual nerve getting pressed.

The long answer

Your funny bone is not a singular bone, but rather the area around your elbow joint. If you’ve ever hit your funny bone, you know it results in this weird, tingly sort of sensation. Why does your funny bone hurt like that when you hit it?

When you hit your funny bone, you’ve actually hit your bent elbow at a channel called the cubital tunnel. This is a particularly vulnerable spot for your funny bone nerve as its protection is limited to a thin layer of skin and fat.

When you hit your funny bone at just the right angle, you are squishing your ulnar nerve – the nerve that connects to the muscles of the forearm, hand, and ring and pinky fingers – into your medial epicondyle bone.

Diagram showing the elbow and ulnar nerve anatomy

"Ulnar Nerve" by BruceBlaus is licensed under CC BY 4.0

The reason why hitting your funny bone feels different than the pain of stubbing your toe, for example, is because it’s simply a different pain sensation. Stubbing your toe results in nociceptive pain which is when the surrounding nerves signal to your brain to inform you to stop stubbing your toe. The funny bone feeling is actual nerve pain and results in a stinging, numbing, and/or electric type of pain.

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Sources

McCallum, K. (2021, February 24). Why Does Hitting Your Funny Bone Hurt So Much? Houston Methodist: On Health. Retrieved September 13, 2022, from https://www.houstonmethodist.org/blog/articles/2021/feb/why-does-hitting-your-funny-bone-hurt-so-much/

Neurosurgical Associates of Central Jersey. (2017, May 15). The Funny Bone (aka the Ulnar Nerve) Is No Laughing Matter. Neurosurgical Associates of Central Jersey. Retrieved September 13, 2022, from https://neurosurgerycnj.com/the-funny-bone-aka-the-ulnar-nerve-is-no-laughing-matter/

 
Caitlin Olson

Caitlin is an amateur nerd who started Today You Should Know because she wanted an excuse to Google all the questions that have popped into my head. What Caitlin lacks in expertise, she makes up for in enthusiasm.

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