Seat depth is measured from the posterior buttock along the lateral thigh to the popliteal fold. What adjustment is subtracted?

• A. Add 1 inch
• B. Subtract 1 inch
• C. Subtract 2 inches
• D. Add 2 inches

Answer: (C)

This item is about getting the seating depth right so the edge of the seat doesn’t press into the back of the knee. When you measure the seat depth from the posterior buttock to the popliteal fold, you subtract a small amount to create a space behind the knee. That knee clearance prevents pressure in the popliteal area, improves circulation, and helps the thigh sit comfortably on the seat without the edge digging in as the knee bends. If you add to the depth, the seat would be too long and press into the back of the knee; if you subtract too little, there wouldn’t be enough clearance. Subtracting that small amount is the correct approach to balance support with knee clearance.