Thankfully with the improvement in human research we have a better understanding of the anatomy of the Sacroiliac Area, however it is still commonly misunderstood. The most important focus for me is through the ASSESSMENT.
Most of you that know me, hopefully can relate to the critical and detailed assessment of your horse performed before I even get my hands on them.
Why do I do this?
To make sure I am taking the WHOLE horse into consideration.
Listening and observing are key parts in assessing and understanding why you and your horse are having the struggles you are having.
Anatomy of the SIJ
Challenges when assessing the Sacroiliac joint function include:
Deep, inaccessible area, covered with a great deal of muscle
multiple connections in one small area
combination of high and low motion joints connected very closely
Multiple ligament connections. At least 5 ligaments acting as stabilisers
The SIJ is situated deep within the body, underneath the pelvis and connects the sacral wing to the ventral aspect of the wing of ilium (see image below). Research has shown that the
sacral joint surface can vary from left to right, and varies in shape between horses (Haussler, 2004). These variations can affect the biomechanics of the individual horse. Dissection of the SIJ highlights that there are various ligaments which support and stabilise the joint, helping in force transfer, shock and absorption.
These ligaments include:
Dorsal sacroiliac ligament - closest to the surface, therefore making it the easiest to palpate.
Ventral sacroiliac ligament - closest to the SIJ itself and can be divided into cranial and caudal aspects.
Interosseous SIL - provides a lateral border - which the deep dorsal sacral muscles pass eg. longissimus, multifidus, sacrocaudalis muscles. This ligament can be found underneath the medial gluteals muscle.
Broad sacrotuberous ligament- wide sheet of connective tissue found underneath the gluteal muscle deep within the body. There are many nerves and blood vessels which interweave within and across the this ligament.
What is the function of the SIJ?
Most of the research based on anatomy and function of this area is comparable to the human field. According to Haussler (2004), the function of the SIJ is to aid in the transmission of propulsive forces from the hind-limbs to the trunk- spine of the horse. A great example is of a horse jumping a fence, visualise the horse before take off and think about the weight which is all on the hindquarters has to be transferred to the front via the trunk and spine.
Another function of the SIJ is to aid in regulating the relationship between locomotion and posture (Neuromotor control) (Hungerford et al 2003).
What does this mean from a training perspective?
My understanding of the SIJ from a training perspective is to focus on STABILITY and STRENGTH, which will help your horse "sit" and carry more weight on their hindquarters.
How do we achieve this?
A well conditioned SIJ must have a equally stable and conditioned illopsoas group of muscles and SI ligaments to help support the skeleton and weight of the rider during tight turns, in show jumping, performing collection in dressage, barrel racing, sliding western halts and ANY MOVEMENTS which ask the horse to push and generate power.
Signs of Sacroiliac Joint Dysfunction:
Poor performance
Reluctant to stand square
Weight shifting
Resistant to the farrier - especially when lifting the hindquarters
Poor hindlimb muscle action
Perceived hindlimb lameness.
Muscle Asymmetry
Uneven stride length
Suspected hock, stifle or back discomfort - further investigation should be performed to eliminate this.
Back pain (supported in human research)
Toe dragging
Plaiting
Lateral canter
Reduced mobility at Lumbo sacral junction
Causes of SIJD:
There are a multitude if factors that will cause dysfunction to the SIJ including:
Trauma - acute/chronic eg. slip, fall
Strain in either the iliopsoas muscle or sacroiliac ligaments eg. repetitive strain injury
A group of muscles that are often overlook in relation to SIJD are the psoas group. Injuries to this group of muscles can occur during a slip or trauma at high speed or an a result of a repetitive strain injury. Muscle tears to the iliopsoas can occur when the lumbo-sacral junction or hip joints are taken to extreme range of movements eg. a horse doing the splits in a field.
The Iliopsoas Muscle and SIJD
We all know that your horse's body is interlinked and therefore during assessment, the better my understanding of anatomy and function, the better chance I have in helping heal your horse's body. Research has identified that weakness of the iliopsoas muscles places additional strain through the SI ligaments which may increased the chance of SIJD. I often see that instability of the SIJ leads to the supporting pelvic and iliopsoas group of muscles to overwork in an attempt to stabilise the joint.
The iliopsoas muscles can be found under the pelvis, deep within the body. Their role is to stabilise the thoracolumbar junction, lumbar vertebrae and lumbo-sacral junction, sacroiliac joints and hip the joints.
The group of muscles which make up the iliopsoas group are called:
Iliacus - helps in protraction of the hindlimb and rotates it outward, flexing the hip joint and stabilising the lumbar vertebrae when the hindlimb is flixed
Psoas Major - similar to the iliacus
Psoas Minor - helps in flexing the lumbo-sacral junction
For more information on anatomy and the images above, please visit my shop for details. https://www.animalchiropractoruk.com/shop
What does this mean?
From a practical standpoint, we want our horse's to be stable, strong and resilient inhand and under saddle. Uneven weight distribution from the left to right hind or right to left hind, is created by asymmetrical forces repeatedly being transferred from the left and right SIJs. Initially this could result in micro tears of the SI ligaments, which if ignored can lead to injury affecting performance and welfare.
Other postural patterns we need to look out for include;
Pelvic posture - changes such a Hunters Bump, Roached back, Double Dip back posture
increased in lumbo-sacral extension/ flexion
retracted or protracted hindlimb stance and positioning
increased hindlimb joint extension
Hindquarter Muscle loss
Exercises to help stabilise and strengthen the SIJ:
Remember that OUR only limitation in training and helping our horses heal is OUR IMAGINATION.
Inhand Exercises:
(Please remember that the exercises below are only a guide and should always be performed and adapted by a professional in relation to your horse)
Reining back
Back lifting exercises
Backwards Shifting
Tail pulls
Pole work at walk
The aim for exercises inhand should be slow, controlled to target the iliopsoas recruitment to active shortening and stability effects through the body.
Ridden exercises
(Please remember that the exercises below are only a guide and should always be performed and adapted by a professional in relation to your horse)
Half halts
Exercises that ask for collection - always start in the walk
Transitions- slow and controlled
Lateral work like shoulder in
Poles in walk and canter- even small bounce exercises
The aim for your ridden exercises is to focus on active shortening and or static stabilisation of the iliopsoas muscle groups.
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If your horse has been diagnosed with SIJD or you can relate to any of the signs and symptoms above, please do not hesitate to contact me.
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