function of the pelvis is to connect the hind limbs of the horse to the axial Ilial wing skeleton. The ilium is the largest bone of If Only They Could Talk the pelvis. The wing of the ilium is covered by the gluteal muscles with a narrow shaft extending back to form part of the hip joint. The ischium forms the back of the pelvic floor and can be palpated on both sides at the base of the Ilial shaft tail. The pubis is the smallest bone of the Pubis Our regular focus on equine health. This month MJR vet pelvis and forms another part of the hip joint and the pelvic floor. JOHN MARTIN discusses two types of stress fractures Stress fractures in the pelvis typically occur in the ilium, most commonly in the which are a common cause of hind limb lameness. wing of the ilium but can also be seen in Hip socket the narrow ilial shaft. These stress John Martin fractures can be present with an acute onset of lameness but can equally present with vague signs of ‘poor movement’ Ischium RACTURES of the pelvis are of hind limb lameness. maintaining healthy bone as the skeleton and stiffness, particularly if present on a common cause of hind limb The pathology of stress fractures has responds to stresses and changes. When a both sides of the pelvis. lameness in the young racing been discussed numerous times in this horse’s bones are subjected to repetitive Diagnosis of these stress fractures can thoroughbred. The severity of section of the Kingsley Klarion, but loading, as is the case with horses in sometimes be difficult, particularly in theseF fractures can range from minor basically in normal bone there is a training, this normal balance of osteoblast mild cases with subtle clinical signs. stress fractures to fatal catastrophic constant process of modelling and and osteoclast activity can be altered, Often horses with pelvic stress fractures fractures. In this article I will discuss the remodelling. This is carried out by two resulting in weakening of the bone which will present very similar to horses which minor stress fractures of the pelvis and types of cells, osteoblasts which lay down increases the risk of fracture. have tied up i.e. have a stiff gait behind Pelvic bone of a horse also stress fractures to the vertebral new bone and osteoclasts which are The pelvis is formed by three fused and with tense and sore gluteal muscles. laminae, which are another common and, responsible for bone resorbtion. This on- bones, the ilium, the ischium and the A blood sample can be taken initially in my opinion, an under-diagnosed cause going process is necessary for pubis on both the left and right side. The to differentiate between the two ridden trotting exercise for the first can present very similar to those with conditions as horses which have tied up couple of weeks. This programme allows pelvic stress fractures, i.e. loss of action, will have elevated levels of muscle the bone a chance to model and remodel, stiffness and a shortened stride. They enzymes. Ultrasound examination of the adapting to the increase in exercise and may also track off to one side when pelvis should also be performed and this hence reduce the risk of further, often trotting in a straight line. It is very can reveal evidence of callus formation unrelated, injury. difficult to image the vertebrae in the on the ilial wing which is evidence of Stress fractures of the lower vertebrae lumbar region with the standard imaging where the body is beginning to heal the in the racehorse are also common,but modalities of ultrasound and radiographs fracture. diagnosed less frequently than pelvic and diagnosis is often only achieved with Callus formation is not always visible fractures. Stress fractures of the vertebrae a bone scan. on ultrasound exam and the absence of typically occur in the vertebral laminae in The rehabilitation programme for abnormality does not mean there is not a the lumbar region just in front of the horses with vertebral stress fractures is fracture present. The final imaging pelvis. The vertebral laminae are flat the same as that for pelvic stress fractures modality used to diagnose pelvis stress plates of bone which form part of the and they also carry an excellent prognosis fractures is bone scanning. outer wall of the spinal canal protecting for a full return to racing. The prognosis for horses returning to the spinal cord. In a post-mortem examination study racing following pelvic stress fractures is Horses with vertebral stress fractures carried out on racehorses which had died excellent. The rehabilitation programme for unrelated reasons there was evidence depends on the initial of pelvic stress fractures in 28% and presentation. Horses Ribs evidence of vertebral stress fractures in presenting with an 50% of the horses examined. These acute lameness require injuries are therefore an important an initial period of box consideration in examining racehorses rest. Once sound at with back pain and hind limb lameness. walk they will begin Dark area: Increased Given the prevalence of these injuries walking exercise for radiopharmaceutical and their sometimes subtle presentation, four weeks followed by uptake on bone scan these stress fractures may be a significant ridden trotting exercise indicating a stress cause of poor performance. for a further two fracture in right weeks. After six weeks lumbar spine the horse should be fit Any horse in training at MJR to resume cantering which is found to have either of exercise. We introduce Pelvis the injuries discussed here will fast work by have all costs of examination and alternating one day imaging covered in the daily cantering and the next CT scan view of the back of a horse training rate. 23