Horse Strains and Tear in the Longissimus Insertion to the Transverse Lumbar

Strains and Tear in the Longissimus Insertion to the Transverse Lumba

This is a very common hyperextension injury which manifests in the midlumbar region. Most strains occur at the junction of the longissimus and gluteal region deep at the tendinous insertions of the longissimus muscle onto the transverse lumbar vertebrae. This region in conjunction with the lumbo-sacral region provides the major source of power for movement and needs to be able to stretch for the horse to be able to hyperextend as needed when the horse ‘lets down‘. This region is therefore stressed at full extension which is why a lot of horses ‘travel up’ in their work but don’t ‘let down’ (i.e when given their head) or even gallop worse when let off the bit due to the muscle hypertonicity and guarding of this region of the back. So unless your putting a really good horse in a bad race to win while hard on the bit, the horse is not going to reach it’s full potential and will start to establish that whenever it lets down it’s going to hurt.

 

I have found that strains and tears to this region commonly occur in gallops and races after horses have trialled first up. What is actually happening here is the horse is trialled with a lack of fitness, after the trail there is usually a massive build up of lactic acid in this region, you will see this when you hose the horse down and there is water trapped in the lumbar midline due to the expansion of the region trapping the water there. This lactic acid starves the region of oxygen and allows inflammation into the muscle and tendinous insertions, so the next time the horse gallops it stresses this weakened structure and
it ends up with a deep tear or strain in either the muscle or it’s insertion.

 

Treatment for this injury can be difficult as the injured region is very deep and little work can be done externally to resolve the pain and spasm associated with the injury. If the injury is picked up early acupuncture can be used to resolve the deeper spasm and hypertonicity so the region can heal properly. However if the injury isn’t picked up early and the horse is continually stressed (i.e galloped) then the body lays down a framework of scar tissue to protect the area, this is something that would work well for the horse in the wild, but with performance horses the scar tissue weakens under pressure and the site re injuries again.

 

This injury is where the shock wave therapy has been of great value by being able to break up the framework of scar tissue then allowing the area to heal properly with muscle fibres and connective tissue. Usually slow exercise, local heat and acupuncture is applied to the area to quicken the healing process and reset shortened longissimus muscle spindle which allows the muscle to increase in length and reduce the stress and the chance of re injury.

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