Let’s get it clear: What makes a good cushion?  4. Contours for Posture and Positioning

Let’s get it clear: What makes a good cushion? 4. Contours for Posture and Positioning

For the clinician, along with for the resident, tissue integrity around the buttocks might well come first when selecting the qualities of a cushion.

In the very first post, we determined the 3 crucial aspects around which a cushion can be examined– functionality, posture management, and tissue integrity.

In the 3rd post, we resolved the benefits of a neutral pelvis and stability for posture management. This short article unpicks additional aspects around posture and positioning that can be boosted by selective contouring.

This is the 4th article in a series which aims to start getting individuals believing more about what enters into a cushion that makes it great for one person, however perhaps not for another.

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Shaping or contouring in cushions can be achieved by fixed parts built into the cushion (e.g. various density or thickness of materials), by adjustability within the cushion (e.g. by selective elimination of air), or by external additions (e.g. with shaped wedges under the cushion).


In this short article, we consider more elements that can be included into the design of a cushion through contouring to offer further postural assistance to the advantage of the resident.

This contouring or shaping can be placed selectively and to various degrees to meet the particular needs of the resident. An alternative ways of managing posture and position, when contouring in or around the cushion is not enough, the application of placing belts and harnesses, and properly placed pads might also be required– either as a last hope, ideally.

Thigh abduction

Therefore contouring can be designed to accomplish specific aims to manage the residents posture and positioning, which might cause improved functionality and/or much better regulated skeletal management, especially throughout growth phases. The downside is that contouring, by limiting some movement, may also have an unfavorable outcome on functionality. In addition, the shapes may physically impair transfers.

Some of these aspects, as well as assisting the occupant to get the benefits of a better posture, will have a positive impact on pressure distribution.

These components can likewise be used to assist manage rotation of the pelvis. In more complex cases including pelvic rotation and/or windsweeping, then the thigh recesses might need appropriate customisation.

As gone over in
Part 3 of this series, the building and resultant stability of the aspects of the cushions style will have major effects– on the residents capability to perform their regular activities while on the cushion, on the one hand, and, on the other, impacts on the control of defects or avoiding the advancement of defects elsewhere in the body.

Figure 1 Optimal thigh angles for femur-hip joint positioning

Figure 3. The association of pelvic obliquity with scoliosis of the spinal column

Figure 2. Greater trochanter unloading choices

On the other hand with the needs to adduct the thighs by a small amount, there will be times where there is a need to restrict the quantity that the thighs abduct. This can be accomplished by increased support constructed into the sides of the cushion– again by utilizing more dense or extra material.

Depending on the degree of versatility of the spine, the shaping of the cushion might be utilized to accommodate the defect, or assist in remedying it. Using a pressure mapping device offers unbiased feedback as to the effectiveness of the particular interventions. The application of an appropriately put placing belt (frequently a rear pull one) can assist in remedying a flexible obliquity2.

If the cushion has sufficient thickness (>> 10cm), and permits adequate immersion in the buttocks location, then some of the pressure from the ischial tuberosities can be unloaded onto the higher trochanters, by the usage of a sub-trochanteral ledge at the side of the cushion. By taking a few of the body mass load onto this area, this also offers higher stability for the resident, since the assistance base is at its best at this point (Fig 2).

Increased lateral support even more back in the cushion can be used to reduce the amount of rotation experienced at the hips, and this can be utilized in combination with a butts recess in the cushion.

Please do take care though: too much unloading can have a negative effect on the hip joint.

Sub-trochanteral assistance

Obliquity management

A more professional piece of posterior lateral support can be to develop a sub-trochanteral ledge. The higher trochanter is the boney prominence sticking out of the side of the femur near where it lies in the acetabulum.

The degree of obliquity is determined by taking a line through the 2 ASISs at the front of the pelvis, and measuring by how many degrees this line deviates from the horizontal. If the ideal side is lower than the left this is a positive angle, however if greater then this is a negative angle1.

In part 3 of this series, we referred to the hips as resembling a basketball, which can turn in all three airplanes. Because part, we covered handling the balls tendency to roll in reverse. Earlier in this short article, weve referenced any tendencies to rotate in the horizontal axis as seen from above from the transverse view. The 3rd direction of possible rotation is seen when viewed from in front– a rotation we describe as pelvic obliquity, where one side of the pelvis winds up higher than the other.

Lateral assistance

Gluteal (posterior) support

The 3rd direction of possible rotation is seen when viewed from in front– a rotation we refer to as pelvic obliquity, where one side of the pelvis ends up greater than the other.

Further items can be found at www.beshealthcare.net. Please contact barend@beshealthcare.net if you are interested in getting additional details on the subject.


A scientific application guide to standardized wheelchair seating procedures of the body and seating support surfaces.

Dr Barend ter Haar has actually been associated with seating and mobility for over 30 years, including lecturing worldwide and establishing global seating requirements.


Figure 4. Pressure map revealing left: pressures, with greatest pressures under the ITs, and right: the gradients from the exact same map, revealing greatest gradients are happening around the sacral/coccyx area

Depending on the degree of flexibility of the spinal column, the shaping of the cushion may be utilized to accommodate the defect, or assist in correcting it. Using a pressure mapping device offers objective feedback as to the efficiency of the particular interventions. Using a pressure mapping system which shows gradients, as well as pressures, can show clearly the possibly destructive forces around locations which are generally out of sight to the naked eye (Fig. 4).

Where the maximum pressures take place are not where the biggest rates of modification take place, and the greater the rate of pressure change, the greater possibility of damaging shear pressure. To what level does your cushion provide contouring around this area (one area of contouring that, incidentally, will not have an adverse result on transfers)?

Click to check out more from the Lets get it clear series from Dr Barend ter Haar.

Including contours to a cushionAdding, for example, a VariliteTM Contoured Positioning Wave Base (CPB) under a cushion, such as a RohoTM cushion, can offer extra support medially, laterally, and posteriorly.

In conclusion

Numerous of us have more tissue than we feel we need around our butts. If we can spread the support of the body more widely over this area, we are taking the forces into tissues well away from improperly covered boney prominences, as described in the paragraph above. Utilizing a pressure mapping system which reveals gradients, along with pressures, can prove the potentially damaging forces around areas which are normally out of sight to the naked eye (Fig. 4).

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Apart from the ischial tuberosities under the pelvis, a significant boney location at danger of pressure and shear injuries, is the sacral/coccyx area at the base of the spinal column– an area that has little skin defense, and an area that has forces from the back support as positions are altered.

There are lots of components that ought to be considered when picking what may be the most appropriate cushion for an individual that work out beyond the instant medical requirements of tissue stability and the occupants requirements for performance. This article offers a number of the pertinent related aspects that can be achieved through contouring of the cushion that can result in a better posture, much better function, and have tissue stability advantages.

A clinical application guide to standardized wheelchair seating procedures of the body and seating assistance surfaces. Denver, CO: University of Colorado Denver, 2013.
BS 8625:2019 Selection, placement and fixation of versatile postural assistance gadgets in seating– Specification (NOTE: Advice on the use and application of this standard is readily available from BES Healthcare Ltd.).