Relative heights of the withers and the tubera sacrale and angulation of the lumbar and pelvic regions in horses with hindlimb proximal suspensory desmopathy, sacroiliac joint region pain and other orthopaedic injuries

Abstract

AbstractBackgroundIn non‐lame horses, the tubera sacrale (TS) are usually lower than or, less commonly, equal in height to the withers. Thoracolumbosacral, pelvic and hindlimb posture/conformation may be influenced by musculoskeletal pain, and development and function of epaxial, pelvic and abdominal muscles.ObjectivesTo investigate relationships between (1) conformation of the withers and pelvis and orthopaedic injuries; (2) tarsal angles and relative heights of the withers and TS.Study designRetrospective cross‐sectional clinical study.MethodsHorses (n = 193) presented for lameness or poor performance with a conclusive diagnosis based on abolition of clinical signs by diagnostic anaesthesia and imaging were included. Polystyrene hemispheres were adhered to the withers, TS and tubera ischiadica (TI). Lateral photographs were acquired with each horse standing squarely, with the head and neck in a neutral position, the metatarsal regions vertical, aligned with the TI. Relative heights of the withers and TS were determined using ImageJ. A line from the TS to the TI relative to the horizontal defined the pelvic angle. A line from the TS tangential to the lumbar region relative to the horizontal defined the lumbar angle. Measurements were compared across four injury groups consisting of hindlimb proximal suspensory desmopathy, primary sacroiliac joint region pain, a combination of both, and other causes of lameness.ResultsThe withers height was ≥TS in 138/193 (71.5%) horses; the withers were lower than the TS in 55/193 (28.5%) horses. Pelvic and lumbar angles ranged from 20.0–42.7° (mean 28.9°, SD 3.4°) and 6.3–18.7° (mean 12.2°, SD 2.3°), respectively. No association between measurements and injury groups was determined.Main limitationsThere was a lack of non‐lame control horses. It was not possible to differentiate between innate conformation versus acquired posture.ConclusionsWithers height was <TS in a larger proportion of lame horses compared with published data for non‐lame horses.