The funny bone that isn’t so funny
Why do they call it “hitting your funny bone” when you hit the inside of your elbow? After all, anyone who has done this knows it’s not funny at all!
The area we’re talking about is actually not a bone at all, rather it’s the ulnar nerve as it passes behind the end of the humerus. The nerve is very superficial through this region and can be easily compressed or irritated by pressure or trauma. In fact, cubital tunnel syndrome (ulnar nerve) is the second most common nerve compression syndrome after carpal tunnel syndrome (median nerve). The nerve can be compressed in 6 different areas so it is easily susceptible to injury. This usually results in a mixture of symptoms and signs including weakness in hand muscles, loss of fine motor skills like writing and holding a pen, loss of power grip. It can result in numbness in the little and ring fingers as well as forearm pain which can even radiate up to the elbow and shoulder.
Some of the risk factors for cubital tunnel syndrome include holding your elbow in a flexed position for extended periods of time, such as when using mobile devices. This is now becoming more of a recognised risk factor as we all spend longer on mobile devices for work and play. Nerves do not respond to stretch very well, and the forced stretch of the ulnar nerve over the flexed elbow only makes the symptoms worse.
Treatment of cubital tunnel syndrome starts with an accurate diagnosis to distinguish it from other nerve injuries including neck problems from disc bulges or arthritis. Once the diagnosis is confirmed then we can start managing it with simple measures like activity modification and ergonomic measures. This could include limiting time spent with a flexed arm, cushioning armrests to prevent direct nerve compression and sleeping with your arm extended.
Once all non surgical measures have failed then surgical decompression is the next step. Sometimes this may need to be done earlier than later especially if the patient starts to notice weakness and muscle wasting, or regular numbness that does not improve. This is a sign of irreversible nerve and muscle damage and surgery is the only way to minimise the damage and start the recovery process.
So the next time you hit your elbow, think about your ulnar nerve and not just about that annoying funny bone that always seems to be in the way!
