Asymmetry – how it affects Soundness

Symmetrical horses are more likely to be balanced. If a horse literally has a leg at each corner, is symmetrical and evenly weight distributing through all four limbs he should be able to move correctly and maintain soundness.

asymmetry 1An asymmetrical horse will compensate throughout his body so weight distribution is not even. This will give uneven wear and tear through the limbs and body. In time muscles, tendons, ligaments, bones, joints, and nerves will all be affected predisposing the horse to uneven gaits and eventually varying degrees of lameness.

Ideally, we should see symmetry between right and left sides of the horse if we draw a line through the middle of the body. Left to right – joints should be the same size and shape, muscle contours should be even, the pelvis should be level and shoulders the same angle and shape and hooves proportional.

Realistically, we often see asymmetry – Shoulder blades at different angles, inconsistent muscle loading, contrasting shaped hooves and joints and differing angles or levels of the pelvis are a few examples to look for.

A horse with symmetrical shoulder blades, angled the same is more likely to take even strides. When shoulder blades are unevenly angled, with uneven muscle development we will see uneven strides. One leg will undoubtedly take a shorter stride than the other. The spine will then compensate for this becoming misaligned and then the pelvis will also compensate causing more unevenness in the movement behind.

asymmetry 2Just like humans horses are born with either right or left sided dominance leading to the beginnings of a crooked horse. As owners, riders or trainers we can often unwittingly increase asymmetry by way we care for and train our horses. For example, if we tie a haynet daily in one corner of the stable so our horse has to pull in one direction away from the wall each time he takes a mouthful he will build more muscle on one side of the neck and shoulders. Similarly if we mount from the ground on the same side every day the horse will brace, building up uneven muscles.

Left uncorrected, asymmetry will lead to training and behavioural issues. As the horse becomes more crooked compensating subtly throughout the rest of his body, he will have less range of movement in one direction. Many symptoms can appear including difficulty bending, cantering on the incorrect lead, bucking, napping, rearing. He may show performance changes, poor gaits or behavioural changes such as biting or kicking when tacked up or brushed. In time this can go on to greatly impair performance and movement and often leads to lameness

asymmetry 3There are many causes of muscular asymmetry in horses. Often it is not just one thing but a combination or a build up of several triggers as can be seen from the list below:

• Falls or any form of trauma whether it is one large impact or several smaller traumas that add up over time.

• Repetitive or one sided activities causing gradual asymmetry in the muscles.

• Conformation affects how the horse balances and redistributes weight.

• Competitions have varying stressors within each discipline.

• Riders issues – novice bouncing / jarring. Experienced – demanding more. Crooked rider causing the horse to shift weight to offset the unbalanced rider thus becoming crooked himself and vice versa.

• Incorrectly fitting equipment / Gadgets.

• Incorrect foot balance / poor farriery.

• Lameness – a horse in pain will alter his stance and gait to relieve pain, redistributing his weight, causing asymmetry.

To summarise – a crooked horse will be less balanced therefore, more likely to be tense and resistant. Tension leads to pain and soreness in the muscles, which become tight pulling on the bones they are attached to misaligning them. This in turn forces muscles, ligaments and tendons to stretch predisposing them to likely strain and injury. Joint angles will also change leading to DJD / arthritis. Prevention is the key to maintaining soundness. Many chronic problems can be prevented by better management, good farriary and the help of therapy i.e. chiropractic/ soft tissue work.

Susan Sargeant – registered Chiropractor qualified to treat humans and animals for more than 14 years. She also holds qualifications in Equine, Canine and Human massage. The combination of these techniques together with her knowledge of biomechanics and rehabilitation offers a unique and in depth treatment for you, your horse or dog. For further information, free spinal checks or appointments please call 07957 509594 or 0208 405 1268

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