Wheelchair Seating & Positioning
Laura Staton, OTR/L, RYT
Staten Island University Hospital
10/19/13

The Pelvis
The pelvis links the vertebral column with the LE’s and defines the base of the trunk.
Pelvic bowl formed by 2 pelvic bones (ilium, ischium, pubis) and sacrum.
Important bony landmarks are ASIS, PSIS and ischial tuberosity (sitting bone).
The 2 pelvis bones attach to the sacrum at the sacroiliac joints with strong ligaments. The SI joints so firmly bind the pelvis to the sacrum that each tilt, rotation and postural shift affects the spine.
A posterior tilt flattens/rounds the lower spine, the anterior tilt increases lordosis.
It’s not the just the pelvis that has to be back in the chair, it’s the sitting bones, which insure proper positioning of the pelvic bowl, sacrum & spine.

The Spine
The spine has 4 curvatures: 2 concave (cervical & lumbar) and two convex (thoracic & sacral).
Cervical & lumbar are lordotic curvatures.
Thoracic & sacral are kyphotic curvatures.
In fetus, the entire spine is kyphotic and curvatures develop as we crawl, sit & walk (specifically the cervical and lumbar curvatures).
All four curvatures act together as a flexible springboard to maintain our upright posture and balance.
When seated, the curvatures are more difficult to maintain (especially with tight hip flexors).

Disc’s
Intervertebral discs are comprised of a gelatinous inner core called the nucleus pulposus (approx 15% of total mass) and confined by the fibrous ring of the annulus fibrosus.
As the spine ages (20-70) the disc dehydrates and vertebral bone loss occurs. The annulus fibrosus takes more weight with compressive forces.
Forward flexion of the spine posteriorly herniates the spine.
Posterolateral herniations are the most common and typically the cause of nerve pain due to the proximity of the nerve root.
Approximately 95% of posterolateral lumbar herniations are at the L4-L5 or L5-S1 vertebral level.
Spinal extension is good for posterolateral herniated discs, flexion is not.

Tonic Labryinthine Reflexes
TLR is an infant reflex which helps baby to master head and neck control, increase tone in trunk and self correct posture & head alignment.
Forward/prone: As head curls in to flexion entire body, UE/LE’s and trunk curl into flexion.
Backwards/extension: As head extends the entire body, UE/LE’s and trunk curl unfold in to extension
Tone can effect w/c positioning

Lab
Forward/Prone TLR – pull your knees up towards your chest and notice what happens to your lower back and trunk: Hip Fx, Kyphosis, Parkinson’s, Spinal Stenosis, MS, CVA, SCI.
Backwards/Supine TLR- Sit on edge of chair and extend head and legs out straight and notice what happens to your body: CVA, SCI, Neurological Disorders, TBI.

What Can We Do To Help?
Prioritize w/c positioning as a part of your scope of practice and treatment time.
Do not be afraid to problem solve with patient (client centered care) and make changes.
Ask for help if you can’t figure out what to do.
Educate yourself and the patient.
Change if it does not work.

Questions to Ask Yourself!
Do they LOOK comfortable in chair?
What are patients here for?
Where do they have pain?
What is their static sitting posture/balance?
Are the hip flexors excessively tight?
Are they w/c bound at home?
Do they complain of pain after sitting in chair?
Are they excessively stiff when they get up?

What Improves Wheelchair Positioning?
The right fit of w/c.
Good usage of equipment (SSI, lumbar support, cushions, back support, lateral support, arm tray, calf panels, knee spreader).
The spine and pelvis (as much!) in alignment as possible.
Neutral pelvis with IT bones touching back of seat.
Back support to reduce pain & increase thoracic spinal /neck extension.
Lateral leaning supported.
Feet and limbs supported.

Basic Guidelines to Follow.
With a THR ALWAYS have a SSI.
With a Hip FX, Stenosis, Low Back Pain, Spinal Surgery, kyphosis – SSI may be highly appropriate.
With kyphosis and back/neck pain lumbar support should be considered.
Any skin breakdown or history of skin breakdown use a specialized cushion.
With excessive lateral leaning consider a specialized cushion to prevent skin breakdown on one side.
Consider a knee spreader to assists with organizing alignment.
With a CVA check to see if they need lateral support? Knee spreader?
If very tight hip flexors use extra cushion to elevate pelvis and stretch front of thighs.

References:
Moore and Dalley (2006). Clinically Oriented Anatomy, 5th edition, Lippincott Williams & Wilkins, Baltimore, MD.
Lasater, Judith (2009). Yogabody: Anatomy, Kinesiology, and Asana. Rodmell Press, Berkeley, CA. H. D. Coulter (2001). Anatomy of Hatha Yoga, Published by Body & Breath, Inc. Albany CA.

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