The medical term for "Mouse hand" "Keyboard wrist" is Carpal Tunnel Syndrome. Carpal Tunnel Syndrome numbness, tingling, weakness, pain and other problems in your hand because of pressure on the median nerve in your wrist. The pressure can come from swelling or anything that makes the carpal tunnel smaller. Many conditions can cause this swelling such as hypothyroidism, rheumatoid arthritis, diabetes, pregnancy and most commonly "making the same hand movements over and over, especially if the wrist is bent down (your hands lower than your wrists) or making the same wrist movements over and over."
Using a mouse regularly involves stationary positions, and small, repetitive and exact movements of the same muscles over and over again for prolonged periods of time. These factors can lead to discomfort, pain on top of hand, around wrist, along forearm and elbow, tingling and numbness in the thumb and index finger etc.
A few small exercises can help prevent "mouse hand":
1. As illustration, close your palms in front of chest, keep this pose and move palms downward until feeling wrists are stretched . Stay for 15 seconds.
2. Keep 2 palms closed, use one palm to push the other one to the most. Stay for 15 seconds.
3. Cross hold 10 fingers, make rotating movements of the wrists. Repeat 10-20 second each hours.
Above information courtesy to: