By using a compact keyboard, one can place one's mouse closer to one's body, which puts less strain on one's neck and shoulders. Unnatural postures when using one's mouse form a risk factor for the occurrence of complaints in one's wrists and forearms.
Ergonomic mouse devices reduce muscle tension in comparison with standard flat mouse devices and are much more comfortable.
Which type of ergonomic mouse is the most suitable depends on the type of work, any complaints and personal preferences.
Evoluent4 Right Small is the vertical ergonomic mouse (version 4) for hands less than about 7 inches or 178mm long.