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Remarks on Ulnar Nerve Compression

Control of the hand is provided to the brain via the radial, median, and ulnar nerve. The default keying position compresses the ulnar nerve.

The ulnar nerve runs through an area called the cubital tunnel in the elbow. This area is colloquially referred to as the funny bone.

A nerve can be modeled as an electrical cable with rubber insulation. Whenever you pinch the rubber tube its internal conductivity reduces. The tube usually quickly expands back to its normal circumference. But if you squeeze that tube over and over and over and over and over for years eventually it will deform permanently.

When you are keying you are almost certainly compressing the ulnar nerve. Stop now before it's too late.

There are two primary reasons why the ulnar nerve is being compressed while keying. The first is that your elbows often need to bend at an acute angle so your hands can reach the keyboard. This is especially true if your keyboard is placed on a high table. You need your elbows to be at an angle closer to 135 degrees. The second reason the ulnar nerve is compressed is that in order to use a normal keyboard one needs to pronate their forearms.1

Let's address how to reduce this bad posture in an ideal manner. The best thing you can do is to cut your keyboard in half and place each half on the outside of your knee. Each half of the keyboard would be rotated 90 degrees from a normal position so that the keys are facing away from one’s body. With the keyboard in this position, your hands can naturally fall into the home row without you having to pronate or bend your elbows.2

You can approximate this by getting a split keyboard with tenting (the ability to tilt them) and getting a keyboard tray - ideally one that also can tilt away from you. For the keyboard I currently use a Kinesis Freestyle Pro 2. I have yet to install a keyboard tray for myself.

If you don't have a keyboard tray nor a split keyboard one tip is to place the keyboard on your lap. It is a decent way to prevent your elbows from bending too much, especially if your desk/table Is too high. If you don't have a split keyboard, there is nothing you can do to prevent the pronation while you type other than hunting and pecking with the outside of your pinkies. (yes I type like that now when I have to.) What you can do is remove your hands from the keyboard and supinate back to resting position constantly to prevent prolonged pronation.

There you have it, some keys to healthy pinkies.

  1. I can reliably reproduce paresthesia simply by putting myself in the naive keying position of bent elbow, pronated forearm. []
  2. Another way to think of this is where would you put the keyboard so that your fingers would be in a good position to strike if your hands were relaxed and in the position they are in during a normal gait. []

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