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EQUINE VETERINARY EDUCATION / AE / SEPTEMBER 2018


racehorse and an understanding of the demands put on the animal need to be considered. Back pain can cause significant issues for a showjumper, who may show a reduction in jumping ability (Jeffcott 2010). It is also important that the owners’ concerns and their expectations for the horse are considered. In some cases, the horse may be presented because it cannot reach the goals set by the owner, rather than because its performance has dropped. It is essential to determine that the horse has already been performing at the expected level, its performance has decreased and that the owner’s expectations are reasonable.


Clinical examination at rest The clinical examination of the horse must form the basis for any diagnosis of TL pain or pathology. Since muscle spasm can occur after riding, the horse should be presented prior to any exercise that day, in a calm and quiet manner. It is important that the veterinarian examines the whole horse in a comprehensive way, starting from the hoof and working up, or from the head and working back towards the tail. Secondary back pain is common, as horses will use compensatory muscles to shift weight off one limb or another when adjusting their gait for lameness. If a problem is found in the horse’s limbs or joints, further evaluation of the horse’s back should be delayed by two or more weeks to allow compensatory pain to abate. During the initial general clinical examination, the


practitioner can focus on those areas that are not specificto horses with TL pain, but can complicate the clinical presentation. It is important to check the head and mouth to rule out dental problems and assess the flexibility of the neck. Any neurological signs should be noted and can be further evaluated during the assessment at work. An evaluation of hoof balance and shoe wear can also aid in evaluating the horse’s condition, with uneven shoe wear indicating the possibility of asymmetric patterns of movement. There are several published methods of examining a


horse for back problems (Munroe 2009; Allen et al. 2010; Jeffcott 2010; Cauvin 1997; Haussler and Jeffcott 2014). Initially, the veterinarian should conduct a visual examination of the horse. The conformation, symmetry and body condition of the horse should be considered. Muscle symmetry from one side to another and on an overall basis is evaluated. Standing on an elevated platform behind the horse is one way of evaluating muscle symmetry. Manual palpation of the back is then performed. With the


horse standing squarely, the veterinarian begins by evaluating the limits of flexion and extension of the back. This assessment can be performed by running the fingers down the back close to the DSPs, starting at the withers and moving through to the coccygeal area. This should cause the


horse to move away from the pressure allowing evaluation of flexion and extension of the spine (Jeffcott 2010). Lateral flexion can be produced by stimulating the longissimus dorsi


at about T16–17 on either side to initiate muscular contraction and lateral movement of the TL spine. Palpation continues with an evaluation of the


supraspinous ligament along the length of the back. Swelling and tenderness in the ligament may indicate desmitis. The tops of the DSPs and interspinal spaces are assessed for deformation and to determine the possibility of overriding DSPs, also known as kissing spines. Pressure is then applied to


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the tops of the DSPs and, while not diagnostic, can be indicative of a problem deeper in the back (Munroe 2009). The muscles of the back should be examined for injury


such as bruising or rhabdomyolysis. Usually these types of injuries will appear as acutely painful areas and the horse will show some signs of general distress (Keen 2011). Mild bruising can be difficult to detect. Palpation of the TL muscles can also reveal areas of tension, tenderness and spasm (Haussler and Jeffcott 2014). Palpation of the back muscles may inadvertently result in


palpation of fascial tissues that should also be considered as a source of pain themselves. Fascial tissues are now considered to serve nociceptive and load bearing functions (Schleip et al. 2010). Fascial and myofascial pain syndromes are recognised in man and present as a complex diagnostic challenge (Milekic et al. 2013). In horses, myofascial trigger points have been recognised as having a role in pain evaluation; however, studies have shown they remain an unreliable indicator (Goff 2016).


Clinical examination while exercising Examination of the horse in walk and trot in hand on a straight line, then all three gaits on the lunge in both directions will aid in ruling out lameness. Observing the horse under saddle or in harness should also be part of a work-up for TL problems and stiffness or reluctance to bend either direction can be reported by the rider. Horses with back pathology will exhibit stiffness in the TL


spine, often have a shortened gait in the hindlimbs and be reluctant to turn in a tight circle. They may also resist backing up. Under saddle, they may roach their backs, show reluctance to move forward and show a lack of impulsion from their hindquarters (Jeffcott 1979a). In some cases, the use of a weighted surcingle might be used to evaluate a horse with load on its back if a rider is not available or it is considered too dangerous to put a rider on the horse (Allen et al. 2010).


Examination of saddle, tack and rider The first saddle is thought to have been invented in 365 AD by the Sarmations. Since then, man has created a whole variety of interesting things to put on horses’ backs to make them easier to ride or control. Harnesses for pulling ploughs, vaulting rollers and Western or English saddles have all come under scrutiny for their effect on the horse’s back, but it is the English style saddle that has received the most attention in the literature. The main question is whether the pressures transmitted through the saddle from the rider cause pain to the horse’s back (Dyson and Greve 2015). An ill-fitting saddle will result in localised pressure points under the saddle. In these areas, perfusion of capillaries can be disturbed resulting in decreased blood supply to the muscle. This leads to tissue hypoxia and a reduction or absence of sweat production, which can be recognised by the appearance of dry areas or saddle sores under the saddle (Von Peinen et al. 2010). In one study, 43% of 205 horses examined had ill-fitting saddles (Greve and Dyson 2015a). The saddle should be assessed for contact under the


panels. Jeffcott et al. (1999) found that the pressure under a saddle should be centred in the middle of the panels, tapering off both front and back and with no pressure through the gullet onto the horse’s spine. An even pressure along the whole of the saddle should occur and the gullet of


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