With every new year, it seems that the newest trend in problems arising from a repetitive movement or cumulative trauma syndrome is diagnosed because a certain sport or activity is simply overdone. We have had tennis elbow, Nintendo thumb and golfer’s elbow. To this list, I would like to add a phenomenon seen more and more frequently…Mouse Arm.
It doesn’t quite have the right ring to it but it is nonetheless on the rise as a formidable dysfunction.
This new problem can cause not only severe elbow and forearm pain, but can also involve pain in the wrist and upper arm, making activities such as using the computer mouse, opening a jar or shaking hands very painful. In addition to the pain, there is a notable restriction in the ability to turn the palm up with the arm extended in front of the body.
Let’s look at some anatomy. The arm is made up of the upper arm bone, or humerus, and two forearm bones called the radius and ulna. These three bones join together at the elbow joint. Besides the simple motion of bending and straightening the elbow, the radius and ulna can also twist over each other to allow a palm up/palm down (supination/pronation) motion.
To test if you have normal forearm motion, bend your elbow 90 degrees and keep it pinned to your side. Your forearm should be horizontal to the floor. Neutral position of your forearm is with your thumb up. Now slowly turn your palm down, keeping your elbow locked at 90 degrees and at your side. You should be able to turn your forearm and hand so that it is facing completely palm down.
Now try going back to neutral (thumb up) and turn your palm up toward the ceiling. Can you get your wrist and hand flat enough to rest a pencil across the crease of your wrist, or does it fall off? If you spend a lot of time working in a palm-down position, such as typing, you may have lost some motion in the palm-up position.
Now, let’s add the upper arm piece to the puzzle. Most people who work sitting or standing with their arms in front of them have a tendency to round their shoulders. This shortens muscles and fascia resulting in arms that tend to turn inward. If you work out with weights, doing biceps curls, chest flys or bench presses without stretching or balancing your workout with the opposing muscle groups, you shorten these inward-turning muscles even more. This is why it becomes more difficult to straighten the elbow and turn the palm up.
Pay attention to the way your hand comfortably rests in your lap. If your thumb rests naturally lower to the chair than your little finger, some shortening in your forearm has taken place. Another clue is how far in front of your body your hands naturally fall when standing comfortably. If your thumb rests against your thigh and your palm faces out to your side, some upper arm and chest muscle and fascia shortening has taken place.
If you have no discomfort, but notice you have tightness and shortening, some simple hints will help. First, make sure you sit with good posture, a lumbar support and keep both feet flat. Check to make sure you have a good ergonomic workstation if you spend time at the computer. Computer mice that allow you to keep your arm and hand in a neutral “thumbs up” position are available.
A simple stretch of turning your palms up several times an hour will also help. Try this both with elbows bent and then with them stretched out straight.
If you have developed pain in your elbow or arm, check with your doctor about physical therapy. The physical therapist should both help treat the problem and check your posture and identify contributing factors to minimize the chance of recurrence.
Remember, awareness of working in unnatural positions for a prolonged period of time is the key to avoiding problems, and Mouse Arm.