Sitting correctly at your computer, by Jennifer Nelson
Hands. Keep your arms by your sides and position bent elbows slightly higher than your wrists, and your wrists slightly above your hands. Wrists should be in a neutral position. You want to be an arm's length from the screen with the keyboard directly in front of you. The keyboard should be 2 inches above your thighs.
Feet. Keep your feet flat on the floor in front of you, hips' width apart, with knees bent at a little more than a right angle. Keep an inch or two between your knees and the seat to allow for better blood circulation.
Chair. Sit so your thighs are horizontal, with your hips slightly higher than your knees. Keep your knees hips' distance apart (do not cross your legs or ankles). A 100- to 110- degree reclined angle in the chair (rather than a 90-degree angle) may be more comfortable. Rest your forearms so your shoulders are relaxed.
Monitor. Place your monitor so your eyes, looking straight ahead, are between the center and the top of the screen with your chin parallel to the floor.
Head. Your head should be in alignment with your back, not leaning forward. Position your shoulders over your hips and your ears over your shoulders.