Wheelchair cushions are cushions specifically designed to provide comfort and protection against injury for wheelchair users. They also aid in properly positioning the user in the correct posture.
Wheelchair users are at great risk for pressure sores. A number of factors are included in the formation of these ulcers including: 
A number of studies point to interface pressure between the body and the seating surface as the primary contributor to the formation of pressure sores. In response, manufacturers have developed a number of wheelchair seat cushion alternatives. Over 200 models of wheelchair cushions were on the market as of 2001.
Characteristics.
Various characteristics, combined with a number of cover material options, offer a myriad of possibilities, which can be manipulated to provide various performance properties. These properties are intended to provide the wheelchair user optimal comfort, stability, and postural support, as well as aid in the prevention of pressure ulcers.
The effectiveness of a particular choice of material and design has high variance with respect to a user's medical needs and activities. For instance, if a wheelchair user frequently moves on rough surfaces, gel cushions are less optimal as they are not as effective at absorbing impact.
Sprigle et al. proposed the following criteria for defining and describing cushion characteristics:
References.
 ;templatestyles src="Reflist/styles.css" / ;