January 9, 2023 – Theme Week Day 2

We’re continuing our theme week on Misnomers! Today we’re talking about the funny bone. There’s certainly nothing funny about hitting your funny bone, and it’s actually not a bone at all! It’s your ulnar nerve, one of the 3 major nerves in your arm. It runs from your neck all the way down to your hand, where it is connected to your middle finger and half of your ring finger.
The ulnar nerve is also known as the “musician’s nerve” because it controls the fine movements of your fingers. The nerve controls hand movement and function, allows you to feel sensations like heat and pain, and helps the muscles in your forearm control your grip.
Like the rest of your body’s nerves, the ulnar nerve is protected by bones, muscles, and ligaments for most of its length. Until that is, it gets to your elbow. As it passes through your elbow, it goes through something called your cubital tunnel, which runs under that little bony bump on the inside of your elbow. When it gets to that point, it’s only protected by skin and fat, which makes it particularly vulnerable to bumps. It’s the longest section of somewhat-exposed section of nerve in your whole body.
So when you hit your funny bone, what you’re actually doing is squishing the nerve up against the bone, resulting in the electric shock-like sensation that shoots down your arm and into your hand. Usually, you can shake it off and it goes away relatively quickly. However, the nerve can be injured by trauma or impingement. The most common injury is called cubital tunnel syndrome, and it basically feels like you’ve hit your funny bone but the pain doesn’t go away. It can happen by things like sleeping with you arm under you, bench pressing, or leaning on your elbow a lot. In some extreme cases, surgery is required to open the tunnel and relieve pressure on the nerve.
It’s unknown why it’s called the funny bone and who was the first to call it that. One theory is that it’s an anatomical pun or play on words because the pain when you hit your funny bone happens when the nerve rubs against the humerus bone in your upper arm. According to the Oxford English Dictionary, it was first used in a poem in 1842, and may refer to the “peculiar sensation experienced when it is struck”. Learn more here.