In "A", the laptop is too high and distant, with the user's arms raised and outstretched, resulting in unnecessary fatigue in the shoulders, neck, back, forearms and hands

In "B", the user has the laptop in the lap, which facilitates good arm position, but the user’s head is dropped, causing muscle tension in the back, neck, shoulders and chest

In "C", the laptop is on a “standard” surface that is too low and close for comfortable viewing, and too high for upper body comfort. Notice that the hands are higher than the elbows, the wrists are resting on the edge of the worksurface, and the low back is not supported. This position increases risk for injury to the neck, back, elbows, and wrists