Lumbo Sacral Disorders
The lumbo-sacral junction is the most posterior junction of the spine which allows for flexion and extension and as the sacral vertebrae is fused there is an increased articulation and range of joint movement, particularly extension. Like the thoraco-lumbar the lumbo-sacral junction plays an even more important role in the transfer of power from the hind quarters in the horse’s propulsion as it much closer to the pelvic/spinal junction. From the surface anatomy, the lumbo-sacral joint lies just anterior to the tuber sacrale (bony prominence at the top of the rump), this joint contains the largest synovial joint pouch of the spinal joints which shows the amount of compressive stress the joint absorbs from the hind limb propulsion.
As with most regions of the spine, the lumbo-sacral region pathology begins from stress secondarily from lower limb stress, in this case this stress is from the forelimbs.
Therefore in performance horses the lumbo-sacral site is a region which is almost always reactive and in some degree in state of hypertonicity. As mentioned above this region has an increased ability for extension of any region of the spinal cord, it is therefore common to see many soft tissue structures of the dorsal lumbo-sacral region strained in performance horses which hyperextend the hind limbs when in full exertion.
One common strain seen with hyperextension is strains in the gluteal muscle anterior-lateral to the tuber sacrale, on palpation of the region there is a tight band of muscle tissue and reactivity which causes the horse to dip under pressure. Another is the lower longissimus insertion to the fascia of the dorsal lumber vertebrae and supraspinous ligament, on hyperextension the tissue is strained which inhibits as spasm locally and extends into the deeper lumber muscles.
With the combination of wear and tear from compensatory forelimb stress and the local muscle strains and other deeper hyperextension injuries leaves this joint prone for degenerative joint disease and even worse ankylosis, this is the bony fusion of the last lumbar and first sacral vertebrae which limits any lumbo-sacral flexion and extension and massively limits performance and putting stress back onto the forelimbs.
Stress from the feet or any pain down the posterior aspect of the forelimb such as the suspensory, sesamoid, caudal knee, flexor muscles and the caudal pectoral muscles will initiate a secondary spasm/hypertonicity of the psoas group of muscles. Strains and tears are common enough in the psoas muscles which develop from hyperflexion of the hind limb in gallops and when swimming. Lumbo-sacral and sacro-iliac pain will also cause the psoas to hypertonify to help splint and protect these associated joints from pain in movement.
The acupuncture work-up can be very valuable in localizing the cause of the pain and hypertonicity in the lumbo-sacral region before any of the known clinical signs manifest and before the problem manifests to the point of lameness. It is also important in determining weather the fore or hind limbs are the cause of the lumbo-sacral stiffness and allow for further treatment of the cause which can be looked into by the vet.
Benefits of acupuncture include:
Common Horse Injuries & Treatments