When talking with health professionals and particularly when I speak with my ‘movement afficionados’ there are many terms that get thrown around and utilised that often render a conversation almost incomprehensible to a bystander or person walking past. It can get confusing and often it is a bit like it’s own jargon with some terms being very similar and indeed meaning the same thing.
One such term is the Anatomy Sling – or Myofascial Sling. This term was coined by anatomists in 1988 and a theory that encompassed more than just superficial muscles was explored to describe the intricacies of movement and stability. The theory proposes that movement comes from not only muscle but other connective tissue such as fascia and ligaments that help to create and support movement. This ‘system’ of support and tissue that create movement began to be known as Anatomy Slings – groupings of muscles and structures that are all important for the myriad of stability and support of movement and our daily actions such as walking.
Most of us have a basic understanding of muscular contractions involved in simple actions. A step for example, comes from hip flexion, which usually involves the psoas or iliopsoas. However with this concept, we look at all the structures that can act on this movement that may influence the motion. When someone is in pain, its not just the one singular muscle that has to be taken into account when trying to rectify a painful action. Hence these slings become vital to understanding where the origin of certain pain in said actions can occur.
Many of these ‘slings’ cross joint spaces and work not only in finite areas such as a hip flexor, but take into account all the structures and areas that remain active in the normal action of a single step. These forces can be located quite distant from the original contraction of a primary muscle and can also cross with various other ‘slings’ depending on the complexity of the motion.
Take for example the pelvic stability. In any singular action simple hip flexion there are multiple slings involved in working to support and maintain the integrity of the pelvis to enable this action to occur with force and strength. The Anterior Oblique Sling (AOS) takes action to stablise the pelvic girdle centering the pubic symphesis (in front of the pelvis behind the gonads) with a binding force that creates support for most hip orientated movements. The AOS includes the internal/external obliques, contralateral adductor muscles via the abdominal fascia. When both these opposing fascial slings are in operation it stabilises the pelvis in walking. Hence in analysing issues with the R hip it may be beneficial to consider the AOS and pay some attention to the L adductors of the leg.
Another sling that demonstrates this factor is the Posterior Oblique Sling (POS) which involves Latissimus Dorsi and the contralateral gluteus Maximus and that all important thoracolumbar fascia. This Anatomy sling is most important in the single leg standing support of a running stride – or if you like, the heel strike. As the body prepares for the hell strike, the hamstring prepares to stabilise the pelvis and act against the quadriceps in the active phase of the stride. The Latissimus Dorsi acts as a counter stabiliser on the contralateral side as the trunk rotates against the Gluteus Maximus once the strike has occurred. All of this happening in a millisecond, but for the purposes of the example, one can see how the latissumus dorsi may be an issue in the heel strike of the runner. It as we say – all connected.
There are numerous of these lines throughout the body and to go into detail about them would require an in depth study of the anatomical particularities of each sling and it’s consequent vector force on actions. So – we won’t do that here. But it standst o reason that in any issue of instability in motion or in weakness in a certain action, analysing and assessing these slings makes for a very thorough approach to understanding external forces that may be acting on an action separate to the obvious muscular involvement. But this is just an example of one of the relative motions that is affected by fascial slings (or lines of contraction) and how that sometimes, inefficiency and thus pain can be a powerful force in trying to differentiate between possible causes of a singular pain pattern.
In this way a therapist may be appearing to work on an area that is completely at odds with the original injury issue and thus a more complete or cohesive treatment may involve working in various areas and not just on the affected side/joint. Therapists are conscious of these presenting factors and so at times, you may find that a practitioner begins working on the opposing (contralateral) side of the body to where you are experiencing the pain. But be aware that this is all to ensure that the complete system is in synergy and not just the symptom is being treated.