 In the United Kingdom wheelchairs are supplied and maintained free of charge for disabled people whose need for such a chair is permanent.Wheelchair seating systems are designed both to support the user in the sitting position and to redistribute pressure from areas of the body that are at risk of pressure ulcers.For someone in the sitting position, the parts of the body that are the most at risk for tissue breakdown include the ischial tuberosities, coccyx, sacrum and greater trochanters.