CMC Wheelchair Seating & Positioning 3 — Questions and Answers
Question 1: Which anatomical landmark is used as the primary reference point when measuring posterior pelvic tilt in a seated client?
- Posterior superior iliac spine (PSIS) (Correct answer)
- Greater trochanter
- Ischial tuberosities
- Sacral crest
Correct answer: Posterior superior iliac spine (PSIS)
The PSIS is palpated and compared to the ASIS to determine the degree of pelvic tilt in the sagittal plane.
Question 2: A client with ALS is progressing toward full dependence. Which seating system feature should the ATP prioritize for long-term positioning as the disease advances?
- Power tilt-in-space with recline and ventilator compatibility (Correct answer)
- Manual lightweight chair with adjustable back
- Reclining back only
- Standard power chair without tilt
Correct answer: Power tilt-in-space with recline and ventilator compatibility
As ALS progresses, tilt-in-space relieves pressure, recline manages tone, and ventilator compatibility addresses respiratory needs.
Question 3: What is the recommended hip flexion angle for most clients in a standard neutral seated position?
- 90 degrees (Correct answer)
- 60 degrees
- 110 degrees
- 45 degrees
Correct answer: 90 degrees
A 90-degree hip flexion angle is the neutral starting position for seating, though individual needs may require modification.
Question 4: Which condition MOST commonly requires an anterior trunk support (chest harness) in wheelchair seating?
- Severe hypotonia with inability to maintain upright trunk (Correct answer)
- Mild spasticity with intact trunk control
- Posterior pelvic tilt only
- Lower extremity weakness only
Correct answer: Severe hypotonia with inability to maintain upright trunk
Severe hypotonia causes trunk collapse; an anterior support prevents forward falling while allowing functional use of the upper extremities.
Question 5: When prescribing a headrest for a power wheelchair user, which adjustment is made FIRST?
- Posterior occipital support height aligned to maintain neutral cervical spine (Correct answer)
- Lateral head support width
- Anterior forehead strap
- Height of the back support
Correct answer: Posterior occipital support height aligned to maintain neutral cervical spine
The primary occipital support is positioned first to maintain a neutral cervical alignment before adding lateral or anterior components.
Question 6: A client with a fixed scoliosis cannot achieve symmetric seating. What is the BEST approach?
- Accommodate the curve with custom contouring and optimize function within the fixed posture (Correct answer)
- Force symmetry with aggressive lateral pads
- Prescribe a recumbent position only
- Refer only to orthopedic surgery before any seating intervention
Correct answer: Accommodate the curve with custom contouring and optimize function within the fixed posture
Fixed deformities cannot be corrected and must be accommodated; the goal is to maximize comfort, stability, and function within the existing posture.
Question 7: Which factor most directly determines the appropriate back support height for a wheelchair user?
- Level of trunk control and functional needs of the upper extremities (Correct answer)
- User's chronological age
- Wheelchair brand
- Cushion thickness
Correct answer: Level of trunk control and functional needs of the upper extremities
Back height is set to provide needed trunk support while leaving scapulae free if the user propels a manual chair or uses their arms functionally.
CMC Wheelchair Seating & Positioning 3
Which anatomical landmark is used as the primary reference point when measuring posterior pelvic tilt in a seated client?