CMC Wheelchair Seating & Positioning 2 — Questions and Answers
Question 1: Which measurement is most critical when determining appropriate seat depth for a wheelchair user?
- Hip-to-popliteal length (Correct answer)
- Hip width
- Trunk height
- Thigh circumference
Correct answer: Hip-to-popliteal length
Seat depth is based on hip-to-popliteal length to ensure proper thigh support without impeding circulation behind the knee.
Question 2: A client presents with a posterior pelvic tilt and sacral sitting posture. Which intervention is MOST appropriate as a first-line seating solution?
- Solid seat insert with anterior tilt (Correct answer)
- Sling seat with hammocking
- Elevated leg rests
- High back with headrest
Correct answer: Solid seat insert with anterior tilt
A solid seat insert with slight anterior tilt helps restore neutral pelvic alignment and reduces sacral sitting.
Question 3: What is the primary purpose of a lateral trunk support in a wheelchair seating system?
- Prevent lateral trunk collapse and maintain midline orientation (Correct answer)
- Increase forward reach
- Prevent anterior pelvic tilt
- Reduce spasticity in the lower extremities
Correct answer: Prevent lateral trunk collapse and maintain midline orientation
Lateral trunk supports prevent the trunk from collapsing sideways and help the user maintain an upright midline position.
Question 4: A user with spastic diplegia tends to scissor their legs together in the wheelchair. Which positioning device best addresses this?
- Medial knee block (abductor) (Correct answer)
- Lateral knee blocks (adductors)
- Ankle straps
- Anterior chest support
Correct answer: Medial knee block (abductor)
A medial knee block or abductor pommel positions between the knees to prevent hip adduction and the scissoring pattern.
Question 5: When measuring seat-to-floor height for a manual wheelchair user who self-propels with their feet, what is the primary consideration?
- Feet must reach the floor flat while maintaining slight hip flexion (Correct answer)
- Seat should be as high as possible for transfers
- Footrests must be used at all times
- Seat height should match the user's sitting height
Correct answer: Feet must reach the floor flat while maintaining slight hip flexion
Foot propellers need a lower seat height so both feet contact the floor fully, enabling efficient and safe propulsion.
Question 6: Which type of wheelchair cushion is MOST appropriate for a client with absent sensation and high risk of pressure injury?
- Alternating pressure or high-specification foam with pressure mapping confirmation (Correct answer)
- Standard foam cushion
- Gel-only cushion without pressure mapping
- Air-bladder cushion set to maximum inflation
Correct answer: Alternating pressure or high-specification foam with pressure mapping confirmation
Clients with absent sensation at highest risk require advanced pressure redistribution confirmed by pressure mapping to identify and eliminate hot spots.
Question 7: In the context of CMC seating assessment, what does 'simulation' refer to?
- Trialing positioning equipment on the client before final prescription (Correct answer)
- Computer modeling of seating forces
- Practicing transfers in a simulated environment
- Using a mannequin to test cushion properties
Correct answer: Trialing positioning equipment on the client before final prescription
Simulation involves trialing various seating components and positions on the actual client to determine optimal configuration before ordering.
CMC Wheelchair Seating & Positioning 2
Which measurement is most critical when determining appropriate seat depth for a wheelchair user?