Medical manual wheelchair incorporates a frame, seat, one or two footplates (footrests) and four wheels: usually two caster wheels at the front and two large wheels at the back. The larger rear wheels usually have push-rims of slightly smaller diameter projecting just beyond the tyre; these allow the user to manoeuvre the chair by pushing on them without requiring them to grasp the tyres. It has brakes that bear on the tyres of the rear wheels, however a solely a parking brakes and in-motion braking is provided by the user’s palms bearing directly on the push-rims.