Positioning the Pelvis: addressing Pelvic Rotation
In previous blogs, we have discussed posterior and anterior pelvic tilt causes, interventions, and goals. In this blog we will address rotation of the pelvis. When the pelvis is rotated, one anterior superior iliac spine (ASIS) is forward of the other. As a result, the client may appear to have a leg length discrepancy as one knee may be more forward of the other. The client will most likely face forward and the spine may rotate with the pelvis as our brain is wired to view the world face-on – rotating the spine in relation to the pelvis.
Causes and Interventions
Range of Motion Limitations Pelvic rotation is most often caused by range of motion limitations in the hips, specifically in hip adduction and abduction leading to a windswept tendency. In a windswept tendency, one leg is adducted and internally rotated and the other leg is abducted and externally rotated. It is tempting to grab the client’s knees and swing those legs into a neutral alignment – but doing so results in pelvic rotation. We need to align the pelvis in neutral rotation and accommodate the windswept tendency. How? Place a lateral knee block at the abducted leg and a medial knee block on the adducted leg to prevent movement beyond which the pelvis can be placed at neutral.
It is tempting to grab the client’s knees and swing those legs into a neutral alignment – but doing so results in pelvic rotation. We need to align the pelvis in neutral rotation and accommodate the windswept tendency. How? Place a lateral knee block at the abducted leg and a medial knee block on the adducted leg to prevent movement beyond which the pelvis can be placed at neutral.
Another consideration in this scenario is nighttime positioning. Nearly all of the clients I work with who demonstrate a windswept tendency have lost range due to their sleep position. In the photos below, you can see that Brady sleeps with his legs in a windswept position. Lacking full hip and knee extension, his legs ‘fall’ to one side during sleep, leading to loss of range. After using sleep positioning interventions to keep his legs in better alignment with his hips during sleep, he regained most of this range. For more information on nighttime positioning, keep an eye out for our next blog!
If hip flexion is more limited on one side, pulling this leg downward may pull that side of the pelvis forward into rotation. In this case, it is important to accommodate the range limitation by closing the seat to back angle at the affected hip. There are cushions available that can accommodate the need for more flexion on one side of the cushion, sometimes called a split angle cushion.
If the range limitations are non-reducible, it may not be possible to place the pelvis in neutral without rotating the spine. It is critical that the client face forward and so the pelvis may have to be accommodated in a rotated position. This may require molded seating for pressure distribution along the posterior pelvis and trunk.
Leg Length Discrepancies
If a client has an actual or apparent leg length discrepancy, using a standard cushion may pull the shorter leg forward, and the pelvis along with it, into rotation. The femurs may actually be of differing lengths, but often a dislocated hip can give the appearance of a leg length discrepancy. The client requires an asymmetrical seat depth so that both legs are well supported without creating pelvic rotation.
If a hip is painful, the client may seek out a position that is more comfortable and this may result in pelvic rotation. It is important to determine if discomfort is present and work with the medical team to remedy the situation.
Tone and Reflexes
Extensor tone or “extensor thrust” can push the pelvis into a rotated position. An Asymmetrical Tonic Neck Reflex (ATNR) leads to increased flexion on one side of the body and increased extension on the other which can also cause pelvic rotation. General positioning strategies which can reduce overall extension include hip flexion and abduction, knee flexion, and ankle dorsiflexion. Positioning strategies to address a posterior pelvic tilt can be used to limit forward movement of one side of the pelvis.
A simple strategy that can reduce rotation is to mount the pelvic positioning belt so that this pulls down on the forward side. This reduces pelvic rotation each time the client is placed in the seating system.
The goal of addressing pelvic rotation is to achieve a neutral pelvic position, if possible, which will in turn support the anatomical curvatures of the spine, distribute weight over the ischial tuberosities and posterior trunk, and provide optimal alignment for stability and function. If the pelvic rotation is non-reducible, our goal is to provide a forward facing position for the client and to distribute pressure.
Michelle L. Lange, OTR/L, ABDA, ATP/SMS