Wheelchair specifications

1. How does the vinyl sling seat differ from the solid seat?
2. How is the seat width determined? What problems result if this measurement is too narrow or too wide?
3. How is the seat depth measured? What problems result from a depth that is too shallow?
4. How is seat height measured? Why are some wheelchairs designed with seats closer to the floor?
5. How is the backrest measured?

Answers:
1. The vinyl sling seat is easy to fold, clean, and is lightweight. The solid seat is more firm and heavy but provides better postural control. It is also difficult to fold.
2. Seat width is 1 inch plus the distance of the widest point of the hips with clothing and braces. A narrow WC results in difficult transfers and skin breakdown. A wide WC compromises truncal support, leading to scoliosis, back pain, and difficulty with wheelchair propulsion.
3. Depth is measured from dorsal buttocks to popliteal fossa and subtract 2-3 inches. If too shallow, ischial pressure is increased and stability of the chair is decreased.
4. Height is measured from the bottom of the heel to the posterior thigh plus 2 inches. Hemiplegic WCs have seats closer to the floor so unaffected leg can propel the chair.
5. If the patient has good trunk control and can propel a WC, the backrest is measured from the bottom of the buttocks to the spine of the scapula minus 3 inches. If the patient has poor trunk control and can propel a WC, the backrest is measured from the bottom of the buttocks to the spine of the scapula minus 2 inches. If trunk control is poor and there is no upper extremity strength, a full measurement is taken going up the back with possible addition of a headrest.