Seat Width: Measure the distance between the buttocks or thighs when seated, and add 5cm to allow 2.5cm of clearance on each side. A seat that is too narrow makes it difficult to get in and out of the wheelchair, placing pressure on the buttocks and thighs. A seat that is too wide makes it difficult to sit firmly, making it difficult to maneuver the wheelchair, causing fatigue, and making it difficult to get in and out of doors.
Seat Length: Measure the horizontal distance from the buttocks to the calf muscles when seated, and subtract 6.5cm from the result. If the seat is too short, the weight will fall primarily on the sitting bones, potentially causing excessive pressure in that area. If the seat is too long, it will compress the popliteal fossa, affecting blood circulation and irritating the skin there. A shorter seat is recommended for patients with short thighs or those with hip or knee flexion contractures.
Seat Height: Measure the distance from the heel (or shoe heel) to the popliteal fossa when seated, and add 4cm. When placing the footrest, ensure the footrest is at least 5cm off the ground. If the seat is too high, the wheelchair cannot fit at the table; if the seat is too low, the sitting bones bear too much weight.
For comfort and to prevent bedsores, the wheelchair seat should be cushioned. Common cushions include foam rubber pads (5-10 cm thick) or gel pads. To prevent the seat from sagging, place a 0.6 cm thick piece of plywood under the cushion.
Backrest Height: A higher backrest provides greater stability, while a lower backrest allows for greater upper body and limb mobility. For a low-back chair: Measure the distance from the seat surface to the armpits (with one or both arms extended forward) and subtract 10 cm from this result. For a high-back chair: Measure the actual height from the seat surface to the shoulder or head of the head.
Armrest Height: When sitting, with the upper arms vertical and the forearms resting flat on the armrests, measure the height from the seat surface to the lower edge of the forearms and add 2.5 cm. Appropriate armrest height helps maintain correct posture and balance and keeps the upper limbs in a comfortable position. If the armrests are too high, the upper arms are forced upward, which can lead to fatigue. If the armrests are too low, the patient needs to lean forward to maintain balance, which can lead to fatigue and affect breathing.
Other wheelchair accessories are designed to meet the needs of patients with special needs. These include increased grip on the handles, extensions to the wheelchair compartment, anti-vibration devices, armrests for the armrests, and wheelchair tables for convenient eating and writing.