Also see Myopathies in Small Animals.
Damage to the muscles is the most common cause of back soreness in the horse. This most commonly involves the longis-simus dorsi muscle, which acts to extend and laterally flex the vertebral column. All or part of the longissimus muscles usually are strained during ridden exercise, and clinical signs are associated with altered performance and back pain of acute or chronic onset. The principal sites of damage are the caudal withers and cranial lumbar regions (just in front of and behind the saddle area). Most of these injuries respond to rest and physiotherapy, although several weeks may be needed for full recovery.
Last full review/revision March 2012 by Stephen B. Adams, DVM, MS, DACVS; Joerg A. Auer, DrMedVet, Dr h c, MS, DACVS, DECVS; James K. Belknap, DVM, PhD, DACVS; Jane C. Boswell, MA, VetMB, CertVA, CertES (Orth), DECVS, MRCVS; Peter Clegg, MA, Vet MB, PhD, CertEO, DECVS, MRCVS; Andrew L. Crawford, BVetMed, CertES (Orth), MRCVS; Jean-Marie Denoix, DVM, PhD, Agregé; Marcus J. Head, BVetMed, MRCVS; C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, DACVS, DACVSMR; James Schumacher, DVM, MS, DACVS, MRCVS; John Schumacher, DVM, MS, DACVIM; Roger K. W. Smith, MA, VetMB, PhD, DEO, DECVS, MRCVS; Chris Whitton, BVSc, FACVSc, PhD