Measuring Guide

Dimension How to Measure Consequences of Improper Fit
Seat Height Measure the client's lower leg from the back of the knee to the floor Seat too high: Client will be unable to reach floor with feet and will slump down in chair to achieve this, adopting a posterior pelvic tilt.
Client should be wearing their usual footwear Seat too low: Increased weight will be taken through the Ischial tuberositles
Seat Depth Measure length from the back of the buttocks to one inch (25mm) behind the back of the knee Too long: Nerves and blood supply to the lower leg will be compressed
 

Too short: More weight will be taken by the buttocks, increasing interface pressure.
Seat Width Measure client´s hips at widest point and add on an extra two inches (50mm) Too narrow: Transfers will be inhibited
  Too wide: Client will tend to lie across chair to increase stability
Backrest Height A higher backrest is more supportive Too low: Client will feel unstable and will slump down in the chair