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Wheelchair Seating & Positioning Guide

Demystifying the provision of wheelchair seating and positioning for healthcare professionals

Seating and Positioning Title Image (1)

Purpose of this Guide

This guide is intended to demystify the provision of wheelchair seating and positioning for healthcare professionals. The aim is to assist healthcare professionals in achieving optimal individualized wheelchair seating to meet the goals for each client by:

  • Understanding the qualifications for both manual and power wheelchairs

  • Identifying the abnormal postures and understanding how ill-fitting wheelchair components lead to postural abnormalities and pressure injuries
  • Understanding how to select the proper seating components
  • Identifying the key components to completing a successful wheelchair evaluation

Keep in mind this guide uses common therapy terms to keep the concepts as relatable as possible. For the most up-to-date, standardized wheelchair terms and definitions, see the “Glossary of Wheelchair Terms and Definitions” found:

Waugh, K; Crane, B; Taylor, S; Davis, K; Cwertnia, S; Brown, L; Saftler, F; Christie, S. Glossary of Wheelchair Terms and Definitions. Published by the University of Colorado, Assistive Technology Partners, through a grant from the Paralyzed Veterans Association. December, 2013.

This guide is not intended to replace the advice of a medical professional. This guide was created using process and funding guidelines for the United States, including Medicare terminology.

To download the Wheelchair Seating & Positioning Guide as a PDF click here.

Look for these info boxes throughout the guide. They include quick tips or takeaways for that section.


ATP: Assistive Technology Professional

NP: Assistive Technology Professional

PA: Physician Assistant

LMN: Letter of Medical Necessity

DME: Durable Medical Equipment

CRT: Complex Rehab Technology

ROM: Range of Motion

ADLs: Activities of Daily Living

MRADLs: Mobility Related ADLs

MWC: Manual Wheelchair

PWC: Power Wheelchair

PPT: Posterior Pelvic Tilt

PSIS: Posterior Superior Iliac Spine

ASIS: Anterior Superior Iliac Spine

IT: Ischial Tuberosity

ELR: Elevating Leg Rest

STFH: Seat-to-Floor Height

LE: Lower Extremity

UE: Upper Extremity




Chapter 1

Getting Started

Getting Started

In the complicated process of getting seating equipment, it can be hard to even know where to start. Our Wheeled Mobility 101 page goes over the fundamentals of wheeled mobility. Click on the links below to learn more about each topic.

Identifying the Need

The Process of Getting Seating Equipment


The Team

Manual & Power Wheelchairs

Our manual wheelchair guide and power wheelchair guide go over in detail the topics associated with manual mobility and power mobility. Click on the links below to see each guide.

Manual Wheelchair Guide

Power Wheelchair Guide

Chapter 2

Abnormal Postures


Looking at Abnormal Postures

When deciding whether or not your patient needs a cushion or back support look at the patient's posture and ask: what is the body doing that it shouldn't be doing? With prolonged sitting, patients begin to shift their bodies into what is known as abnormal postures to seek stability and/or alleviate pain or pressure. It is crucial that you understand what you are looking at and decide whether your goal is to correct or accommodate for the abnormal posture.

Spinal and Pelvic Anatomy Refresher

Before we start talking about abnormal postures, let's take a quick look at the spine and pelvis and what a neutral pelvic posture looks like.

Spine and Pelvis Anatomy Refresher

Neutral Pelvic Posture

Neutral Pelvic Posture

Abnormal postures are grouped into 5 categories and are as follows:

Click on any of the abnormal postures to see in more detail what the pelvis, spine, and head are doing in each posture and what goals to strive for in correcting or accommodating the abnormal posture.

Anterior Pelvic Tilt Wheelchair View
Anterior Pelvic Tilt with lumbar lordosis with or without neck hyperextension. 

Posterior Pelvic Tilt Wheelchair View
Posterior Pelvic Tilt with thoracic kyphosis with or without forward neck flexion; also referred to as sacral sitting.

Pelvic Obliquity Wheelchair View
Pelvic Obliquity with scoliosis with or without lateral neck flexion.

Pelvic Rotation Wheelchair View
Pelvic Rotation with rotation of the spine with or without lateral neck flexion.

Non-reducible vs Reducible Postural Abnormalities

How do I know when to correct the postural abnormality and when to accommodate for it?

Each abnormality is either FIXED/Non-Reducible or FLEXIBLE/Reducible.

Understanding whether the postural abnormality is non-reducible or reducible helps decide if we need to ACCOMMODATE for or to CORRECT the postural abnormality. 

Non-Reducible = Accommodate

When a posture is non-reducible, the skeleton does not move out of that posture. The patient needs equipment that will accommodate the abnormal posture, providing optimal support and pressure redistribution.

GOAL = Preventing further progression

Reducible = Correct

Reducible means that the posture is flexible, or can be changed. However, not all reducible postures can be corrected to neutral.

GOAL = Prevention from becoming a non-reducible posture

The standardized terms in the wheelchair seating world are now Non-reducible for Fixed and Reducible for Flexible.

Why? The term non-reducible better accounts for the potential worsening  of a postural abnormality where the previous term "fixed" did not.

Understanding Reducible Posture

The goal when correcting a reducible posture is to achieve their most neutral posture that can be maintained over time with proper support in order to optimize function.

Reducible to Neutral
Reducible to Neutral

Posture can be moved with support to a neutral/midline position. If they cannot maintain midline over time, the goal is to find the most neutral position for the client and support them to that point.

Reducible NOT to Neutral
Reducible NOT to Neutral

Even if a client cannot achieve a truly neutral/midline posture, if the posture  can be adjusted with support towards midline, it is considered reducible.

Reducible PAST Neutral
Reducible PAST Neutral

With support, if a posture can be moved beyond a neutral/midline position, it is reducible with the goal to position them in midline.

If they cannot maintain the reduced posture over time, your goal may need to shift to accommodating like you would for a non-reducible posture. However, continue to provide interventions that will prevent it from becoming truly non-reducible.

Issues with the Current Wheelchair System

An improper seating system can actually cause or progress abnormal postures.

How Does an improperly fitting wheelchair impact my patient’s posture?

The wheelchair system can definitely be at fault when the patient is sitting in an abnormal posture. Here is a closer look into seating dimensions and how an ill-fitting wheelchair component can be the culprit behind the body moving into unwanted, harmful postures.

Find out how common seating system issues can affect posture and how to potentially troubleshoot the problems:

Seat Dimension Issues
Seat-to-Floor Height Issues
Back Support Issues
Leg Rest Issues
Arm Rest Issues
Head Support Issues

Chapter 3

Measurement Guide

Measurement Guide

Our beginner's guide to fundamentals of wheeled mobility, Wheeled Mobility 101, goes over the therapy evaluation along with how to measure for properly fitting wheelchair components. We'll go over briefly the measurements. Click on the link below to see the full measurement guide for wheeled mobility. 

How to Measure for Properly Fitting Wheelchair Components

Measuring Guide

Measuring Guide - Full List
You will need to perform the following required measurements when choosing the best fitting equipment. Click here to download an easy-to-use measurement form to document your findings in the field.

  • Shoulder Width (A)
  • Chest Width (B)
  • Hip Width (C)
  • Between the Knees (D)
  • Top of Head (E)
  • Occiput (F)
  • Seat to Top of Shoulder (G)
  • Inferior Angle of Scapula (H)
  • Seat to Elbow (I)
  • Elbow to Tip of Fingers (J)
  • Upper Leg Length (K)
  • Lower Leg Length (L)
  • Foot Length (M)

Chapter 4

Principles for Equipment Choices

Choosing a Wheelchair Cushion

Finding the perfect wheelchair cushion for your client can be a daunting task with hundreds of options out there. The first step is knowing what your client qualifies for. This is determined by diagnosis and documented postural presentation. There are resources that can help you find the right code but don't be afraid to ask for help from your trusted ATP/dealer! 

Once you know the code, you still have so many options. What then?

There are three areas to understand when choosing a wheelchair seat cushion:

Methods of Pressure Redistribution

Cushion Geometry 

Cushion Medium

When choosing a cushion, always keep in mind your goals for the pelvis. For example, if the pelvis is in a non-reducible posture, your goal is to accommodate that posture through cushion geometry and medium. 

If the posture is reducible, you will look for contours and a medium that can correct the pelvic position.

Methods of Pressure Redistribution

Pressure cannot be eliminated in seating, so instead, we must focus on the redistribution of pressure. Taking the same amount of pressure and spreading it out over a greater surface area will do this (as illustrated below), but even then, there are different methods in doing such.

Surface Area Pressure

Offloading / Partial Offloading:


The principle of taking pressure off of a small surface area and loading it onto a greater surface area that can withstand more pressure and prevent unwanted skin breakdown.



The principle in which a material allows the body to compress or “sink” into it to provide some pressure redistribution with increased surface area contact.

Immersion and Envelopment


The principle in which a material allows the body to compress or “sink” into it and the material conforms to the body’s shape to provide further pressure redistribution and reduction of peak pressures.

Cushion Geometry

Click on the links below to learn more about each style of cushion geometry along with the benefits and considerations associated with each.





There are different components associated with contoured cushions. Click on each geometric component to learn more.

Adductors: Tapered or Straight
Medial Abductor
Posterior Pelvic Well

Cushion Medium

Understand the available mediums when choosing a cushion. No matter the geometry, the quality of the medium will affect the application of the cushion. Each has benefits and considerations, click on each medium to learn more.




Gel/Fluid Inserts


What are some things I need to consider when looking at each cushion medium?

Weight of the cushion
Each medium has different properties, making them lighter or heavier.

Support/stability needs
Each medium has different qualities that make them more or less supportive, which impacts how long a patient can sit in their wheelchair, ease of transfers, and pelvic posture when weakness is present.

Remember to think of the functional and postural goals of your client!

Foam is not foam is not foam! The quality and properties of foam, or any cushion medium, affect the application and effectiveness of a cushion. Be an advocate for your clients and choose QUALITY products!

Choosing a Back Support

There are a few key questions to ask yourself when deciding if the manufacturers back support should be replaced with an off-the-shelf back support:

  • Is your patient immobile?
  • Does your patient have a postural abnormality that affects pelvic and trunk stability and alignment?
  • Does your patient require assistance to sit unsupported?
  • Does your patient complain of pain while sitting in the wheelchair?

If you answered yes to any of these questions, then, without a doubt, replace the sling back with a separate off-the-shelf back support.

If your patient qualifies for any model wheelchair, they automatically qualify for at least a general use back support. Always consider replacing the sling back with an off-the-shelf option to provide better pelvic and trunk positioning.

The right back support is an essential part of an optimal seating system. Here are some of the important ADVANTAGES of an off-the-shelf back support:

  • Provides depth and angle adjustability through hardware
  • Provides trunk stability to promote functional sitting
  • Works with the cushion to provide pelvic stability
  • Provides increased pressure redistribution at the trunk and pelvis
  • It can minimize the progression of abnormal postures
  • Decreases pain by increasing stability and pressure redistribution

Even when dealing with a more "typical" spinal posture, a solid back support can provide stability to conserve energy for self-propulsion

What do we need to consider when choosing a back support?

There are three areas to understand when choosing a wheelchair back support, click on each area to learn more:

Shape of the shell




Back support goals:
  • Maximize patient function at his/her optimal capacity
  • Stabilize the pelvis to maximize function of the cushion
  • Provide posterior thoracic stability
  • Facilitate maximum pressure redistribution to minimize high peak pressure areas
  • Maintain and support natural curves of the spine

Wheelchair Accessories

As in most things, LESS is MORE and this is certainly true in wheelchair positioning. If you take your time in selecting the right model and size wheelchair and then select an appropriate cushion and back support, accessories may not be needed. Too often accessories are used as “band-aids” for a less than optimal wheelchair seating system. When used the proper way, they can be the finishing touch to achieve the best posture possible for your patient! Below is a list of different types of wheelchair accessories; click on the accessory to learn more.

Upper Extremity Supports

Lower Extremity Supports

Lateral Trunk Supports


Chapter 5

Common Misconceptions & Conclusion


Common Misconceptions

There are a few misconceptions that seem to persist in the world of wheelchair seating and positioning. Click on each link below to get an in-depth look at each misconception.

The Elevating Leg Rest Misconception

The Wedge Misconception

Problems with Sliding out of the Wheelchair


It is important to keep the following goals in mind for your patient both short-term and long-term and then do the best you can! 

  • Maximize patient comfort
  • Minimize pain
  • Correct deformities when possible
  • Prevent further deformity
  • Prevent pressure injury
  • Increase functional safety and independence 

Click here to download the Wheelchair Seating & Positioning Guide as a PDF

Click here to view the list of references

Remember, there is NO cookbook solution to wheelchair seating and positioning. Use your clinical reasoning skills to figure out what's best within the given parameters.


For more information click here to contact your local representative.

The Wheelchair Seating & Positioning Guide is available for download. Click here to get your PDF copy.

All contents © copyright 2019 Permobil. All rights reserved.

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