Explainer | Facts about the elbow: how to avoid tennis elbow, why it’s called the funny bone and where ‘elbows off the table’ came from
- Doctors explain what can go wrong with the vital, sensitive joint, how to prevent tennis elbow and how it is treated, and one activity you really should avoid
- We explain why it’s called the funny bone and why we can’t lick our own elbows, and explore the origin of the adage that elbows should be kept off the table
You might not give it a second thought – unless you’ve hurt it – but the elbow is one of our body’s major joints. It allows us to carry out several everyday actions, such as rotating the hand or lifting an object.
Involving three major bones and many ligaments and tendons, the elbow is prone to injury. We consider how to care for the joint, whether it is only tennis players who suffer tennis elbow, why it’s called the funny bone and why we’re not supposed to put ours on the dinner table.
The elbow is where the humerus, which runs from the shoulder, meets the radius and ulna bones in the forearm. These bones are held together by tendons and ligaments, the most important being the ulnar collateral ligament (UCL) and the radial collateral ligament (RCL). The UCL connects the three bones and the RCL is on the outside of the elbow and prevents overextension.
Another important part of the elbow is the ulnar nerve – commonly known as the funny bone. The origin of this phrase is uncertain; it could be a play on the word humerus, or because of the “funny” sensation we get from hitting the nerve – a mixture of pain and a tingling sensation that extends to the fingertips.
The ulnar nerve runs from the spine to the shoulder and down to the fingers, and is protected most of the way by bones and muscles.
However, when it reaches the elbow it travels through a 4mm wide unprotected channel – the cubital tunnel. That’s why, when you hit your elbow in just the right spot, you directly hit the nerve, resulting in that “funny” feeling.
Dr Diane Tai, a Hong Kong specialist in orthopaedics and traumatology, explains that the elbow is prone to overuse injuries such as tennis elbow. The repetitive movement in certain sports or other daily activities triggers inflammation of some tendons.
The human hand – our evolutionary advantage
Tennis elbow causes pain around the outside of the elbow and forearm. The condition – clinically known as lateral epicondylitis – is often triggered by tennis players hitting backhand strokes.
Despite its name, the condition can be caused by any repetitive motion: painting, using hand tools, chopping ingredients, and even using a computer mouse.
So what should you do if you suffer from tennis elbow? First, stop the activity that caused the problem and rest the elbow. At home, you can apply a cold compress several times a day and take over-the-counter painkillers.
More severe tennis elbow may require treatment: physiotherapy, steroid injections or shock wave therapy – non-invasive delivery of acoustic waves to the injured site to help it heal – injections of platelet-rich plasma (a blood component containing proteins that help blood to clot and promotes healing), or surgery.
Hong Kong orthopaedic surgeon Dr Sally Cheng adds that the elbows can be prone to injury because we use them to break our falls, or they might suffer a direct hit resulting in bone or ligament injuries.
The elbow’s epicondyles – the two round bits sticking out at the end of the humerus – are particularly vulnerable, and bone fractures here are the most common short-term elbow injury.
Using a trampoline is a frequent cause of elbow fractures and breakages. According to a 2014 report in the Journal of Paediatric Orthopaedics, between 2002 and 2011 a million people in the United States had to go to hospital after a trampoline accident, and 19 per cent of their injuries were elbow fractures.
In Hong Kong, trampolining was once a part of school physical education classes, but after a trampoline accident in 1991 that left the victim a quadriplegic – paralysed from the neck down – its popularity dwindled.
Trampoline centre Ryze proves a summer hit with Hong Kong youth
Of course, prevention is better than cure, and Cheng and Tai offer advice on how to avoid elbow injuries. Tai recommends specific exercises to strengthen the forearm muscles; using an elbow splint or band if you are experiencing pain; using a lighter racket with a larger grip for tennis or badminton, and; doing warm-up stretches before sports – especially rackets sports.
Cheng suggests regular stretching, avoiding repetitive stress injuries, eating healthy food and drinking plenty of water to help prevent problems.
Another peculiarity of the elbow is that while the ulnar nerve makes the bone extra- sensitive, the elbow’s skin is the opposite – you can pinch the skin as hard as you like without causing yourself pain. This is because the skin on your elbow has fewer sensory neurons than many other areas of the body.
And what of the age-old adage “elbows off the table”? The phrase could originate from the Bible’s Book of Ecclesiasticus, which declared putting one’s elbows on the table as outrageous as breaking an oath.
Some believe that the ‘rule’ dates to earlier civilisations in which it may have prevented the risk of violence; keeping elbows off the table served to keep dinner guests in their seats. In today’s world, the reasoning is similar; keeping elbows off the table stops us elbowing our neighbour in the chest while knocking over their wine glass.
Funny bones, tennis elbow and table manners – this joint is not simple. Whether you play a lot of tennis, practise elbow licking, or spend time on a trampoline, spare some thought for that arm-bending hinge.
