Many people aren't bothered at all by a big typing workload, but an extended mouse session has them howling with pain. So it's no wonder that mouse wrist (a term sent to me by subscriber — and sufferer — Mark Worden) is becoming one of the most common RSI conditions. It has been around since about the mid-90s, not long after most of us brought those electromechanical mammals into our computing lives:

"Jervis, an admitted technology buff who often wears two arm braces to alleviate pain in his 'mouse wrists,' says technology has helped improve the way his classes are taught." —Melissa DeVaughn, "Charles Jervis," Roanoke Times & World News, May 16, 1995

The mouse can burden not just the wrist, but the entire arm, so the phrases mouse arm and mouse arm syndrome are also becoming popular:

"The Ullman Mouse is ... held like a pen and that, says Ullman, is where its secret lies and why it won't cause injuries like normal mice. By using it like a pen, muscles in the forearm and upper arm are at rest and the user's hand and forearm are in a more natural position, rather than being twisted around horizontally, as they are when a mouse is used. It's this position which causes mouse arm syndrome, a type of RSI that affects millions." —Martyn Williams, "Swedish researcher claims mouse breakthrough," Network World, April 2, 2001