Hitting your ‘funny bone’. It’s one of the only injuries that we can laugh about, literally. It’s even become an expression that we use for something funny that catches us off guard. The sensation is so strange that we’re not sure whether to laugh or cry. However, contrary to its title, the pain that we feel from hitting the funny bone isn’t from a bone at all – it’s a nerve.
The ulnar nerve is the longest unprotected nerve in the human body, which is why it is so prone to injury. It begins at the base of the neck, extends down through the elbow and out to the hand, ending in the pinkie and middle part of the ring finger. For most of its way through the arm, it’s protected by bone, muscles and ligaments. At the elbow though, it passes through the cubital tunnel, a vulnerable place for impact that is only protected by fat and tissue. When hit, the ulnar nerve sends a wave of pain running down through the arm, radiating to the fingers and back, creating the painfully-funny sensation that makes us laugh with pain.
What’s in a name?
There are two possibilities as to why it is called the funny bone. It may derive from an anatomical pun, because the ulnar nerve runs down the Humerus Bone, which sounds like humorous (pretty funny right?). The next explanation is simply the effect of hitting the ulnar nerve, which causes the odd feeling that induces laughter. Either way, both seem fitting.
When it’s no laughing matter
Most of the time this isn’t a real injury at all but a bump or bruise, but it can be more serious. Sometimes the ulnar nerve gets compressed through impact, leading to temporary immobility in the hand and arm as well as a ‘pins and needles’ feeling. Anti-inflammatories will bring down swelling, allowing the nerve to decompress and to regain mobility. But if immobility persists and the ‘pins and needles’ turn to numbness, see an orthopedic specialist right away, as the ulnar nerve may be damaged. Even though it may be inaptly named, the sensation is still very real. At least knowing a little more about this common and minor injury may help you ‘laugh it off’ a bit quicker.