(5) Wheelchair Measurements

10/12/2026

Three variables considered for wheelchairs

1. balance and postural control in sitting

2. ability to achieve neutral sitting posture

3. degree of postural support needed to achieve neutral posture

Process for obtaining wheelchair

Physician referral for w/c assessment → PT evaluation → ATP (assistive technology professional) evaluation

Wheelchair considerations

Home accessibility, caregiver needs, transportation, funding, and patient goals/desires

PT considerations:

• endurance, physical abilities (MAT assessment), size & weight, diagnosis, cognition, pain/sensation, skin issues

5 Year Rule

Client must remain in same w/c for 5 years (or longer) unless they have a change in medical condition

Justification for w/c use

Wheelchair propulsion test

Timed propulsion over fixed distance

Count push strokes

Quality of propulsion

Document pain levels and pulse ox

Postural assessment

Environmental needs

Environmental Measurements

Must consider width of doorways, hallways, and other factors for w/c use

Chart - Parts of a Wheelchair

MAT (mechanical assessment tool) Evaluation

Purpose = determine if there are barriers to functional, comfortable, and upright seated posture

Postural assessment done in supine (gravity eliminated) and sitting

***Skin Integrity (current pressure ulcers, scar tissue)

Spine and pelvis mobility

***Orthopedic deformities (flexible? fixed?)

Abnormal tone

***Static and dynamic balance

Joint ROM must be adequate for seated posture

ROM and strength must be adequate for mode of drive control (manual? powered?)

Body measurements for w/c prescription

Tips for measurements

1. All measurements on firm, flat surface in the target posture

2. Use hard measuring tape (not one that can bend and wrap) to avoid measurement errors of increased circumference or length

3. All measurements should be taken straight across the body

4. Use measurement forms to take all necessary ones properly and document properly

5. Don’t forget excess tissue; measure in ideal posture that is realistic to have throughout the day

6. Don’t forget to look for limited hip ROM and tight HS; often culprits of poor pelvic position!

Chart - Necessary measurements

Seat Width

Seated, widest distance from hip to hip

Add ~2 inches to allow space between arm rest and each side of the hip

Considerations:

• 1 ¼ - 2 inches added = room for clothing (e.g. coats), prevents skin irritation between thighs and armrests

• too wide = difficult to propel

• avg. size = 18”

Seat Depth

Seated, distance along thigh from back of hip to the knee

Subtract ~1-2 inches to allow space between back of knee and wheelchair seat

Considerations:

• too long = skin irritation and breakdown on back of knee, poor postural support

• too short = less support under thighs and more pressure on buttocks

• avg. size = 16”

Floor to Seat Height

Seated, distance from the fold in back of knees to bottom of heel

Add ~2 inches to allow room for footrests to clear the floor

Considerations:

• too high

  • w/c difficult to fit under desks/tables

  • feet unable to touch floor when footrests removed

  • wheelchair more difficult to propel

  • incr. risk of tipping

• too low = footrests hit the floor and increased buttocks pressure

• standard height 18-19”

• cushion may add 2-4” (need to know cushion height)

• foot propulsion utilization (hemi-height)

Seat Back Height

Seated, distance from buttock to bottom of scapula

Add or subtract depending on needs for postural support, as a higher seat will offer more trunk support

In general, height must not interfere with shoulder movement

Considerations:

• too high = poor upper trunk posture, limit shoulder ROM for propulsion

• too short = poor posture, inadequate trunk support

• cushion may add 2-4” (need to know cushion height)

Armrest Height

Seated, elbows bent to 90deg, distance from buttocks to tip of olecranon

Add 1” plus cushion height to allow for neutral shoulders

Considerations:

• proper height for upright posture

• too high = pressure on elbows, may cause shoulder impingement

• too low = poor, leaning forward posture

Backrest Width

Seated, width of chest at level of top of backrest

Add 3/4”

Considerations:

• too wide = interfere with shoulders, inadequate postural support

• too narrow = skin irritation, discomfort

Camber

Angle of wheels in relation to vertical

Considerations:

• more camber (greater angle from vertical) = upright stability, improved turning maneuverability

  • also protects hands as propelling through narrow doorways

• too large = difficult to maneuver through tight spaces

• implicated in adaptive sports

Center of Gravity - Axle Position

Position of axle in relation to seat of wheelchair

Considerations:

• affects stability and manual propulsion

• more posterior = increased stability, but difficulty reaching handrims for propulsion

• more anterior = decreased stability, but easier to propel wheels and pop wheelie

  • in general, wheels placed in most forward position allowing user to easily propel without compromising stability

• in-line with GHJ

  • axle backward = decr. tippiness

  • axle forward = incr. tippiness

• amputee axle to accommodate CoG change (axle back)

• axle heights: (changes elbow flexion angles)

  • lower axle for higher rear of seat to floor height for taller person

  • raise axle for lower rear/front of seat height (dump, access under tables)

Hanger Angle

Angle where footrest bars meet seat of wheelchair

Considerations:

• smaller angle = more knee flexion, but easier to turn w/c

• larger angle = less knee flexion, but forward instability (feet in front of w/c)

  • also requires more turning space

Propulsion Mechanics

Shoulder ~70º abducted

• begins extended, IR

• ends flexed, ER

Consider well-developed shoulder flexors, internal rotators and adductors with poorly developed external rotators and thoracoscapular muscles

Constant propulsion predisposes pt. to RTC impingement

Longer push strokes (greater contact angle) = more efficient, less likelihood of injury, fewer pushes needed

Pelvic Positioning

Assess for neutral, ant/post pelvic tilt, pelvic rotation, pelvic obliquity, windswept deformity

Importance:

• pressure relief

• postural issues

• functional movement + reaching

  • core stability and positioning affects ability to use extremities efficiently

Postural Deformities; Flexible vs. Fixed?

May present with postural deformity from contractures with apparent scoliosis

Windswept deformity = scoliotic curve due to compensatory pelvic obliquity

Accommodate: often need to allow lower body rotation to achieve more functional upper body and face-forward positioning

Manual Wheelchairs

Temporary uses (TKA, THA, Fx)

Full time mobility (SCI, TBI, CP, SB)

Rigid/Folding

One-arm Drive (CVA, UE Amputee)

DME Wheelchairs (K0001-K0003)

Standard w/c in hospitals/nursing homes purchased in bulk for short term transportation needs

Most appropriate for use on firm, level surfaces; not for full-time or long-term use

Complex Rehabilitation Technology (CRT) K0005

Tilt-in-Space

Custom Manual w/c

0001 = standard manual

0002 = standard hemi-height manual

0003 = lightweight manual

0004 = high-strength lightweight manual

0005 = ultralight manual (higher-level complete/incomplete SCIs)

0006 = heavy-duty manual

0007 = extra heavy-duty manual

Power Wheelchair Drives

Mid-wheel = smallest turning radius

Rear-wheel = widest turning radius

Front-wheel = better front access