Sheared Heels and the Correlation to Spontaneous Quarter Cracks

Sheared heels as a clinical entity and a cause of lameness were first described in the veterinary literature 35 years ago (Moyer and Anderson, 1975). A sheared heel is defined as a hoof capsule distortion resulting in a proximal displacement of one quarter / heel bulb relative to the contra-lateral side of the hoof (Turner, 1992). The disparity between the lateral and medial quarter / heel bulb is generally 0.5 cm or more and is measured from the coronet to the ground or to the shoe. When the weight of the horse is not distributed uniformly over the entire hoof during the landing and/or weight bearing phase of the stride, one section of the foot, usually a heel bulb and accompanying quarter, receives a disproportionate amount of the total load. This repetitive disproportionate load causes the proximal displacement of the heel / quarter of the hoof capsule while the increased compressive stresses placed on submural tissue in this area predispose the foot to various injurious conditions including a quarter crack(O’Grady, 2002, O’Grady, 2005). While the diagnosis of a sheared heel is straight forward, the aetiology of the condition may be misleading and the farriery employed in the treatment is often based on opinions. Sheared heels appear to develop as an adaption-distortion of the hoof capsule as a consequence of limb conformation that result in an abnormal strike and loading pattern of the foot on the ground. Prevention or treatment of limb conformation is only possible in the foal, therefore in adults; therapy is directed toward managing the distortion of the hoof capsule. Spontaneous quarter […]