In seating measurements, which of the following statements is correct?

• A. Width should be increased by 2 inches; depth should be decreased by 2 inches
• B. Width should be decreased by 2 inches; depth increased by 2 inches
• C. Width increased by 1 inch; depth decreased by 1 inch
• D. Width increased by 2 inches; depth decreased by 2 inches

Answer: (D)

The main idea is fitting the seat to the sitter by balancing width and depth to avoid pressure and to provide proper support. You want a seat that is wide enough for the hips and thighs without crowding, and you want the front edge not to press into the back of the knees. A typical approach is to make the seat width slightly larger than the widest part of the hips—about 2 inches more—to allow clearance for clothing and to prevent tissue compression. For depth, you measure from the back of the pelvis to the popliteal area and then subtract about 2 inches so the front edge doesn’t press into the back of the thighs and the knee angle stays around 90 degrees. So increasing the width by about 2 inches and decreasing the depth by about 2 inches best meets these goals, giving comfortable support and proper knee clearance.