It is well documented that horses can suffer with back problems and they tell us by their actions. Sometimes the signs are blatant – for instance the horse stops jumping, or displays an obvious aversion to being saddled. Most of the time the signs are much more subtle. The animal may slightly change its way of moving in order to avoid pain and if untreated this becomes a chronic and long term problem, the slight change of gait becoming a progressive shortening of stride and a reduced level of performance.
The power source in the equine comes from the hind limbs propelling the body forward. If there is pain within that area the animal will use less power – and therefore go slower, or be unable to clear fences – than if it felt no pain. Traditionally we look at a horse being ‘trotted up’ in a straight line as a way of assessing soundness. This is an adequate measure in many cases where there is obvious lameness in one limb however a lame horse can ‘trot up’ sound and this shouldn’t be the only measure of soundness. Other tests such as trotting on a circle in both directions, on both hard and soft surfaces should be used. Assessing the animal at a walk on a level surface and observing from both the rear and from the side is also a very useful tool in diagnosing a slight lameness or restriction of gait. What manifests itself at a walk will still be there at a gallop. And knowing how the animal moves when sound and supple is key to knowing when something is starting to go wrong – perhaps catching a small problem before it becomes a serious lameness issue. Just saving itself from a fall or slip up when in the field can be enough to cause a problem.
A momentary error of judgment by horse or rider can force a horse to use its athletic ability to get out of trouble. A twist or over-big jumping effort can be enough. The horse can go on to complete the course or win the race that day but later, when the body has cooled down and the tired muscles are trying to recover pain can develop because of that over exertion. A subluxation may have occurred An almost imperceptible lameness or a restriction of free movement of the limbs can make all the difference between winning and losing. A slight ache or low grade back pain can make all the difference between staying the distance and tailing off last. Do horses have an ‘off day’? Or is there an underlying problem which is preventing full extension, making the animal hold itself back in order to avoid pain? The Spinal Cord is the keystone of the body. Maintaining its health and integrity is imperative in maintaining the health and wellbeing of the body as a whole, and doubly so in the case of a performance athlete.
The protection of the spinal cord is paramount in the actions of the horse or any vertebrate. The nervous system controls the whole body, with nerve control of practically every cell of the body. Subluxations or trapped nerves can interfere with the ability of the nervous system to function to the best of its ability both in control and in counteracting disease. Manipulation is therefore a means of reducing these subluxations to improve the functioning of the whole body. The skeleton is responsible for supporting the body and providing it with a strong framework consisting of rigid components which can move relative to each other at articulating joints. The spinal column provides protection to the spinal cord.
If a joint in the spinal column were to be dislocated that would result in damage to the spinal cord and paralysis or death. Between each pair of vertebrae a pair of spinal nerves leave the spinal cord through a small ‘gap’ in the muscles, ligaments and other soft tissues. A subluxation is where the joint between two bones is misaligned – muscles go into spasm and can pull one of the bones of the joint slightly out of alignment. If a joint is subluxated then the two surfaces are not quite in the correct position and nerves become impinged or ‘trapped’.
A nerve which has become trapped cannot send signals to muscles therefore function is affected. The equine athlete, and particularly the race horse, is highly susceptible to damage of the back, neck and poll. The body is put under a great deal of stress and pressure during breaking and fitness work whilst still immature. Added to this the horse must learn to carry the weight of a rider on its back and to balance itself with this shifting weight. Exertion such as galloping and jumping stresses the musculoskeletal structure and it is whilst under stress and when fatigued that injuries can occur more easily. The neck, chest withers and shoulders are of paramount importance to the action of the forelimbs.
The main nerves which feed the forelimbs leave the spinal cord between vertebrae in the lower neck and chest area (C6 –T2). If a horse struggles to flex and bend its neck to each side, up and down, shows stiffness or pain reactions it will cause restricted limb action, reduced ability to gallop, reduced speed, reduced stamina and reduced performance. As a highly strung and active animal the young horse is likely to be ‘sharp’ and difficult to handle during breaking. Whilst lunging they are prone to over-excitement resulting in leaping, bucking, rearing, spinning around etc - once backed they are still likely to display these behaviours. Rearing followed by unbalancing and going over backwards, or rearing whilst tied up with the entire weight of the body being taken over the poll region by the headcollar can lead to damage of the neck, withers and back. Rearing and hitting their head on a stable beam or flinging up the head and hitting it on the door frame or in a vehicle are all possible scenarios for damage to the poll and neck resulting in tension, pain and the development of other symptoms.
Sensitive withers can be just ticklishness but could also be soreness from the front limbs and neck. Concussion can travel right up the forelimbs resulting in sore withers. Of course a horse of any age can become sensitive in the neck and poll and often we do not know what they have done or when they have done it, unless it can be attributed to a particular incident such as a crashing fall or getting cast in the stable. Often the problem exists without explanation and could have been there for months or years – like living with a permanent head ache. Treatment with manipulation is straightforward and can give lasting relief. The main nerves which feed to the hind limbs leave the spine in the lumbar and sacral region (L4 - S2) and inflammation, soreness and pain in this area can and does cause the horse to take a shorter hind stride or unequal hind strides. The result of this will be a reduction in power leading to slower galloping speed and/or reduced stamina and failing to stay the distance.
The inexplicable poor performance of any horse could be attributed to any of the above. Fitness to do the job required is a vital part of injury prevention. Weeks of slowly building up the workload are necessary to attain the level of fitness needed for the job in mind. Additionally training involves keeping the body free from aches and pains which might lower the level of performance that the individual can attain. During training nerve damage can and does occur which will cause restrictive movement and a loss of straightness. This can be due to conformational defects, concussion, over-exertion, muscle strain, or injury.
There are no absolutes when it comes to conformation of the limb and the flight of the limb through the phases of a stride. Generally we look at conformation relating to the breed or type of the animal when standing. Some abnormalities or defects may only be evident during a phase of stride and may affect a pair of limbs or a single limb. Abnormal development within a joint can also cause a limb to exhibit a lateral gait defect. Normally the joints such as fetlock, carpus and tarsus work in a hinge-like fashion, backward and forward in a straight line parallel to the horse’s midline. An abnormality can produce a swivel-like motion and cause the limb to arc in flight. Even if a horse shows all the conformational traits that theoretically add up to straightness, if it experiences pain in any part of its body it may break all of the conformation rules in order to use its limbs in a manner which creates the least stress and pain.
An injury or soreness in a limb can cause a horse to protect one portion of the limb when landing, subsequently altering the arc of the foot’s flight. When a horse has pain in a part of the body other than the hooves or limbs, its balance during movement may be negatively altered as it compensates for the soreness. Back soreness can mimic lower limb lameness and alter foot flight. A variety of factors can cause a horse to carry its body in a stiff or crooked fashion. Sometimes the stiffness or pain is subtle but just enough to prevent the horse from tracking straight. As most people will know from personal experience – back pain reduces their ability to move freely, slows them down and if left untreated is debilitating and can lead to a long term loss of full musculoskeletal function together with general irritability.
This is no less the case in the horse and it does not necessarily mean that the horse is lame only that performance has been reduced. A horse suffering with back or neck pain will be unable to gallop as fast as it did prior to the injury, will be unable to ‘stay’ as far. The pain will restrict it and it will be unwilling to keep galloping thereby being seen to fade in the last furlongs or in severe cases never being able to lay up with the pace and being adrift from the offset. By being vigilant to the signs pain and of over-exertion and by allowing for recovery of the musculoskeletal system after work these problems can be minimised. The signs can be subtle but they are there – sometimes rest is needed, sometimes an injury has occurred which will require treatment.