Trackballs and Thumbs: Friends or foes?

Trackballs and Thumbs: Friends or foes?


The trackball styled mouse has been around for what seems like forever. Originally invented as device to help the military plot points and track aircraft in post WWII in Great Britain, the trackball has changed greatly in design and function compared to its late 40’s origins.

While the trackball undoubtedly changes the posture and alters the workload in the mouse arm to alleviate pain in wrists and shoulders, we must wonder for the all the problems trackballs solve, do they create a scenario for other mouse-related RSI issues to arise? As you have probably guessed by the title of this blog, we are talking about the thumbs. Specifically, the carpometacarpal (CMC) joint.

Let us look at the two main types of trackball mice and how a potential CMC joint overuse injury is possible.

Centered (finger) trackball

The centered trackball is a static pointing device, that relies on the user to roll the trackball with the middle three digits of the hand and use the thumb and pinky finger to perform left and right clicks, respectively. While this keeps the wrists and shoulders in a relaxed position, centered trackballs will put your thumb in a precarious posture and has a high probability for overuse considering how frequent a left click is needed.

Side (thumb) trackball

Like the centered trackball, the trackball mice with the ball on the side are designed to be static on the desk and reduce the amount of wrist and shoulder movement. While it is good for the wrist and shoulders, side trackballs are designed to rely on the thumb for all cursor control which puts users at a much higher risk of developing RSI’s in the CMC joint.

How overuse can injure the CMC joint

In a normal thumb joint, cartilage covers the ends of the bones — acting as a cushion and allowing the bones to glide smoothly against each other. With thumb arthritis, the cartilage that covers the ends of the bones deteriorates, and its smooth surface roughens. The bones then rub against each other, resulting in friction and joint damage. Historically, people in the 40+ age range are the most susceptible, but In the age of smartphones more and more people are finding that they are developing issues with their CMC joints earlier from overuse, especially when given a trackball to cure other ailments.

Unimouse protects the thumbs

Our Unimouse is designed to relieve the stress on the thumb, with a fully adjustable thumb support, allowing users to rest their thumbs comfortably. This not only eliminates the harmful workload put on the thumb by trackballs, it also eliminates any gripping or squeezing of the mouse putting your thumbs in a constantly relaxed, neutral posture.

So give your thumbs a break and check out the Unimouse today!

Learn more about the Unimouse.