Careful attention must be paid to anthropometrics when manufacturing seating for diastrophics. It is not a matter of simply downsizing a normal office chair, as if manufactured for a child. Little people do not have the proportionality of limbs demonstrated throughout the population at large.

When fitting a little person for a chair, the most important measurement is the popliteal-to-buttock length (back of the knee to back of the buttocks). In this case study, this person's popliteal-to-buttock dimension was 8½". Obviously, a standard 18" deep seat pan would prevent her from even contacting the backrest and getting any lumbar support. Sitmatic manufactured a petite seat (PS) at 16" deep, but this would have still been too deep. It was impossible to make the seat pan any shorter because the mechanism underneath the seat, with a 10½" length, would protrude out and hit the occupant in the back of the legs. Sitmatic solved the problem by increasing the backrest thickness 8" by adding multiple layers of foam beneath the contoured top layer.

Because the work surface was at a standard 29" height, Sitmatic originally manufactured a chair with a footring to provide leg support. After trying the chair, we discovered this person experienced discomfort when her knees were flexed more than 30°. Sitmatic solved the problem by customizing a footbar to support to support her legs at the proper angle. A lower seat height cylinder was used to allow easier ingress and egress. An air lumbar bolster (AL) was installed to fine tune the lumbar shape. Wide armrest caps, that rotate in, were used to accommodate a narrow elbow-to-elbow distance.

Sitmatic: Building the chairs you need.