The "Uncrossed Bones" Lie: Why That Green Skeleton Diagram is Fake

If you’ve ever frantically browsed for ergonomic office gear at 2 AM because your wrist hurts, you have definitely seen The Chart.

It’s the defining image of vertical mouse marketing—famous on manufacturers' websites, scattered across Amazon product listings, and buried in ergonomic white papers.

• Top Image: A person using a vertical mouse. Their arm bones are perfectly parallel, like smooth railway tracks. The arm glows Green. Green means health. Green means "Buy me."
• Bottom Image: A standard mouse user. Their arm bones are twisted like a braided pretzel. The arm glows Red. Red means danger. Red means "You are breaking your body."

The sales pitch is simple: "A standard mouse crosses your bones. A vertical mouse uncrosses them."

It sounds scientific. It looks convincing. It is also an anatomical lie.

We decided to expose this illusion the simplest way possible: We bought some colored tape, and we fired up an X-ray machine.

(Note: Our brave model for all photos and X-rays is Dr. Sig, who subjected his own arms to radiation for the sake of the truth.)

The Experiment: Measuring the "Twist"

To show you what is actually happening under your skin, we marked Dr. Sig's forearm bones with tape:

• Orange Tape: The Radius.
• Blue Tape: The Ulna.

We then compared what the Tape (skin) looked like against what the X-ray (bone) looked like in three key positions.

1. The "Standard Mouse" Position (Palm Down)

First, let's look at the position the marketing tells you is "dangerous." Dr. Sig placed his hand flat on the table, as if holding a standard mouse.

2. The "Real"Vertical Mouse Position

Here is where the marketing falls apart. Most vertical mice (like the Logitech MX Vertical) are not perfectly vertical. They are tilted at approximately 57° to 60°.

If we hold the hand at a true 90° vertical angle, we can't click the buttons effectively. So, we tested the actual position you use with these mice: a 57° inward tilt.

The Reality: Look closely at the X-ray. The bones are DEFINITELY crossed.

Because the mouse is not fully vertical, your arm is still in a state of partial pronation. The Radius (Orange) is still crossing over the Ulna (Blue). It is structurally almost identical to the "bad" flat position, just rotated slightly less.

The marketing diagrams showing straight, parallel lines in this position are erasing anatomical reality to make a sale. At a 57° working angle, parallel bones are physically impossible.

3. The "Impossible" Standard (Palm Up)

So, when are your arm bones actually parallel? When do you get that "Green Skeleton" alignment?

Dr. Sig to flip his palm completely up, facing the ceiling (a position called Supination).

The Problem: Try using a mouse like this. Go ahead, lay your hand on your desk palm-up. Now try to click a button. You can’t. This position is anatomically "perfect," but functionally useless for working at a computer.

4. The "Natural" Test: Crossed Can Be Comfortable

There is one more thing the diagrams don't tell you: "Crossed" does not necessarily mean "strained."

The crossing of the Radius and Ulna is a brilliant evolutionary feature that allows humans to use tools on flat surfaces. It is not a bug; it is a feature. In fact, biomechanics suggests that the membrane connecting your two arm bones is often quite relaxed when the hand is palm-down.

Try this simple test yourself: Sit at your desk and place your forearm on the table. Let it go completely limp. Does it hover in the air in a vertical "handshake" position? No. Does it feel twisted and painful when your palm touches the desk? Likely not.

For most people, resting the hand palm-down (or semi-prone) feels stable, planted, and relaxed. The table supports the weight of your hand. In contrast, holding your hand vertically often requires a subtle balancing act to keep it from tipping over, or it forces you to rest your weight on the narrow, bony side of your pinky finger. The "crossed" state is often the most natural way for your body to rest on a horizontal surface.

The Verdict

The visual foundation of vertical mouse marketing—that it "uncrosses" your bones to save your wrist—is a myth.

• Standard Mouse: Bones Crossed.
• Vertical Mouse: Bones Still Crossed.
• Marketing Diagram: Bones Parallel (This only exists in cartoons).

The Takeaway

If a vertical mouse feels better for you, that’s great! It might be helping you by keeping your wrist from rubbing against the desk or changing your shoulder posture. But please, don't buy one because you think it magically untwists your skeleton.

As Dr. Sig's X-rays prove: unless you type with your palms facing the ceiling, your bones are always going to cross. That’s not a medical emergency; that’s just being human.