I started this blog trying to pull apart the many elements of “desk-job-itis” that contribute to a person having painful forearms. It is a complicated web with many moving parts.
Unsurprising really, as the human body is an intricate construction with a myriad of interdependent elements and we are all individuals when it comes to how we maintain our health (even that varies across time). Add a layer of “life has impact” (injuries and illness) and also consider that we each have a collection of good and bad habits in how we use our body... I guess that’s why we see health professionals to unravel the snarl and guide us back to better function.
Hands are awesome. Awesome in how they are constructed and how they function. Having an opposable digit – the thumb – is often cited as one of the reasons humans evolved to be a successful species. I find hands almost as fascinating as spines (!), but their function can be broken down into a system of levers and pulleys driven by the power of muscles and coordinated by the messages from the brain, which are conducted to the region via the nerves.
So, in essence, for the hand and forearm to work the way they were built, we need three things:
Humans were built to walk all day hunting and gathering. Our shoulders are designed to throw things (e.g. a spear). How often do you think a city office worker walks all day and throws spears? Maybe in a parallel universe, but I can’t say I’ve once had a person walk into my city practice and proclaim that is how they spend their days! Is it any wonder then, that without regular maintenance of the frame, it deteriorates and doesn’t work as well as it can? It’s easy to imagine this being the case in central structures like the spine, but it holds true for peripheral structures like the hands and arms too.
Sitting, well, that blows the alignment right up front. The human frame is just not built for sitting. An immaculate ergonomic desk set up + exemplary technique in using the workstation will minimise the poor alignment of the frame that is caused by sitting, but time will unravel that effect. Long periods of sitting (that is over 20-30 minutes) will fatigue some tissues and compromise the feedback system the brain relies upon to pre-plan movement and coordination of muscle groups. The sum total is the brain increases tone in the long strap muscles of the body to brace it and keep it safe which translates to feeling stiff [read more here]. This can be managed: by using a standing station (and alternating between sitting and standing through the day) and establishing good habits around moving often (every 20-30 minutes).
Re-focussing on the arms though. Classically, sitting plus time leads to a posture where the forward curve in the upper back (thoracic spine) increases. This does two things that impact our arms: it places the head out in front of the body (a.k.a Forward Head Carriage, FHC ~ read more here) which can impact on the nerves that travel between the brain and the arm; and, over time, it causes the shoulder girdle to rotate forward which messes up the alignment of muscle action through the shoulder girdle and upper back.
The next issue for the desk worker is where they position their arms while they work. Computer mice that roam off to the extremities of the desk space serve to create a long lever of the arm which biomechanically drags off the upper back and neck. This will further aggravate the cervical and upper thoracic spine (a.k.a. neck and upper back). When it comes to the way the frame is put together, it’s best to keep your elbows glued to the sides of your ribs…this takes a little juggling with the keyboard and mouse to make it work, but it can be done. Occasionally, a different breed of mouse or keyboard is required for optimal function.
Biomechanically, your fingers work through a really cool pulley system. The muscles on the back of your forearm (wrist and finger extensors) pull the fingers back and the muscles on the palm side of your forearm (wrist and finger flexors) pull your fingers towards your palm. The forearm muscles do this via tendons that run under ligaments at the wrist and attach to the finger bones in the hands (phalanges).
Typing requires an intricate dance of these muscles that the brain coordinates and conducts with great aplomb once it has learned to. Just like learning to ride a bike, typing is a learned motor skill that requires practice. However, whether you have an ability in the realm of 90 words per minute or are a “peck things out with a limited number of fingers” typist, it is a repetitive action. Repetitive activities result in wear and tear and deterioration of tissues if you don’t do the appropriate maintenance.
There are two classic forearm problems that “desk-job-itis” can contribute to: tendinopathies at the elbow (lateral and medial epicondylitis) and Carpel Tunnel Syndrome (CTS).
Elbow tendinopathiesare colloquially known as “Tennis” and “Golfers” Elbow respectively. In Tennis elbow the wrist extensor tendon is impacted and the person has pain on the outside of the elbow. With Golfer’s elbow it is the wrist flexor tendon at the elbow that is impacted and accordingly, the pain is located on the inner elbow. The mechanism of injury is however, the same.
With tendinopathy, the muscle gets too tight and drags on the insertion point and there is microtrauma to the junction between the muscle and the ligament or between the ligament and the bone. Repeated aggravation causes chronic inflammation at this point. Using it at this stage just plain hurts, as you would expect of an inflamed and angry tissue. People often have a lot of trouble not using it so it can heal (you can imagine that telling a desk worker not to type for the 8 weeks it takes tendons to heal [read more here] does not go down well!) and thus, months of elbow pain lies this way as we slowly rehabilitate the tissues while the aggravating activity persists…
With elbow tendinopathies, classically, typing can contribute to lateral epicondylitis (tennis elbow), but it can be caused by other repetitive actions including (but not limited to) tennis (!) or using a screwdriver or hammer for an extended period. This can also happen on the inside of the elbow – there it is called medial epicondylitis (golfer’s elbow).
...is not fun either.
The pulley system at your wrist is mechanically pretty awesome. The eight little bones of your wrist (carpel bones) sit in two curved rows such the they create a hollow that the tendons that close the fingers into a fist travel through (the wrist and finger flexor muscles in the forearm power these). The tendons are kept in place by the flexor retinaculum (or transverse carpel ligament) which runs across the top of the hollow creating the “carpel tunnel”. As the tendons travel through the carpel tunnel they travel in their own individual sheaths so they glide smoothly. The median nerve and the blood vessels that supply the hand also travel through the carpel tunnel.
The carpel tunnel is designed beautifully, but it is a limited space that has no give. Anything that takes up extra space (e.g., compressing the area through poor posture of the arms over time when typing, or any inflammation in the carpel tunnel because of overuse or due to some other health condition) can compress or irritate the medial nerve as it travels through the carpel tunnel. This can result in hand and forearm pain, pins and needles or numbness. This situation is likely to get worse with time and prognosis is much better if it’s dealt with earlier.
Please note, it is also possible to get pain, pins and needles and numbness in the arms and hands caused by irritation of the nerves in your neck. It is also possible to have aggravated nerves in your neck and at the carpel tunnel concurrently. I see this in desk workers often. It is important to address both elements.
So, I’ve spoken about the essentials of desk ergonomics and good desk worker “hygiene” before. It’s easy to forget your arms when your spine is talking to you. Please remember to stretch your forearms (wrist flexors and extensors) at least twice a day ~ before you begin and again later in the day. More is great. It’s an essential part of the maintenance of your second greatest tool at work – your body (the greatest being your brain). If you’d like some clarification on how to perform these stretches, please ask when you come in for your next appointment. Call 8221 6262 to make a booking at the Adelaide Chiropractic Centre now.
Prevention! Prevention! Prevention!!!