Postural assessment of the pelvis poses difficult questions. In this post massage therapist Jane Johnson, MCSP, MSc identifies and answers a common question.
Illustrations and photos in this blog are taken from Jane’s books Postural Assessment and Postural Correction.
Assessing pelvic tilt – a challenge for you!
If you missed Jane at Quantum Metta, don’t worry she has done another video for us below with the answer.
Assessing low back pain
When assessing a patient with low back pain, a clinician will often observe the patient’s posture, paying special attention to the position of the pelvis in the sagittal (side) view. This is because the pelvis can ‘tilt’ anteriorly (forwards) and posteriorly (backwards) and in so doing, affects a change in the orientation of bones in the lumbar spine. It has been postulated that exaggerated lumbar postures contribute to low back pain.
In a neutrally positioned pelvis, the lumbar spine has a gentle lordosis (inward curve) (A). As the pelvis tilts anteriorly, this curve becomes exaggerated (B), and when the pelvis tilts posteriorly, the natural lordosis of the lumbar spine is reduced (C).
Importance of postural assessment of the pelvis
Why should we care about assessing the position of the pelvis? We should care because if pelvic (and lumbar spine) posture contributes to back pain, it may be possible to reduce pain by changing posture.
When the pelvis is anteriorly tilted, soft tissues (ligaments, fascia, skin, muscles, nerves) of the low back are compressed. In this posture, pressure on intervertebral discs is altered, affecting nutrient exchange (Adams and Hutton 1985). Joints of the spine called ‘facet’ joints are subject to increased stress and there is a possibility of strain to the capsules of these joints (Scannell and McGill 2003).
When the pelvis tilts posteriorly, loss of the natural lumbar curve reduces the spine’s ability to withstand compressive forces. There is increased compressive stress on the front part of lumbar discs as well as increased hydrostatic pressure in the nucleus of the disc (Adams and Hutton 1985).
In both postures, there is an imbalance in flexor and extensor muscles which could in turn adversely affect hip function. There is also an imbalance in the longitudinal spinal ligaments running down the front and back of the spine and this imbalance could affect the spine-stabilizing capabilities of these ligaments.
Some therapists, therefore, observe the position of the pelvis to help determine the shape of the lumbar spine and consider whether this is a contributory factor to pain or dysfunction.
What to look for
One way to check for the ‘tilt’ of the pelvis is to check the positions of the Posterior Superior Iliac Spines (PSIS) relative to the Anterior Superior Iliac Spines (ASIS). This helps determine whether the client has an anterior or a posterior tilt in the pelvis.
Another method is to observe the position of the ASIS relative to the pubic bone. When the pelvis is in a neutral position, the ASIS is roughly aligned with the pubis vertically (D) but falls anterior to the pubic bone when the pelvis is tilted anteriorly (E) and posterior to the pubic bone when the pelvis tilts posteriorly (F).
However, assessment of the position of the pelvis and shape of the lumbar spine using the bony landmarks can be difficult with overweight clients. Therefore an alternative method of assessment is needed.
Before you watch the second video, can you think of a non-invasive method of determining the position of the pelvis other than by observing the position of the PSIS and ASIS?
An alternative method for assessing pelvic tilt
If you wish to determine whether a client is standing in an anteriorly tilted pelvic position with an increased lumbar curve associated with this position or, if they are in posteriorly tilted pelvic position with a reduced lumbar curve a quick and easy method is to ask your client to adopt these pelvic positions and see how easy they find this.
(It is almost always necessary to demonstrate to your client how to perform these movements first.)
If a client cannot easily perform an anterior pelvic tilt, assuming they have no serious spinal pathology that would prevent them adopting such a position. The reason might be that they are already in an anteriorly tilted pelvic position.
If a client cannot easily perform a posterior pelvic tilt, the reason might be that they are already in a posteriorly tilted pelvic position.
Examples of conditions that would limit movement of the lumbar spine are fused lumbar vertebraes and ankylosing spondylitis. In such cases, this simple test would not be used to determine pelvic position.
To sum up, the pelvic posture a client is likely to have is the one they find difficult to adopt when asked, because they are already in that pelvic position.
More from Jane
In September 2018 Jane presented a free Webinar for Human Kinetics. Titled Advice, exercises and treatments for low back pain. Click on the link to watch now.
Jane followed this post up with a post on how to correct an anterior pelvic tilt position using simple stretches and a trick with a towel!
This post on postural assessment of the pelvis is the second post from Jane. Check out last week’s post How to prevent and treat knee hyperextension.
Jane has written 5 books for Human Kinetics:
Jane has also done a webinar for us in the past Postural Correction: An introductory guide you can view this for free on the Human Kinetics website.