AAEP 360° Back Pain and Pelvic Dysfunction / 2018 Functional Anatomy and Biomechanics of the Caudal Trunk and Pelvis Kevin K. Haussler, DVM, DC, PhD, DACVSMR vertebral regions; however, the spinal curvature formed by the Author’s address—Gail Holmes Equine Orthopaedic Research apices of the thoracolumbar dorsal spinous processes does not Center, Department of Clinical Sciences, College of Veterinary correspond to the curvature of the vertebral bodies, since the Medicine and Biomedical Sciences, Colorado State University, lengths of the spinous processes vary considerably in the Fort Collins, CO 80523; e-mail:
[email protected] thoracolumbar vertebral region. The supraspinous ligament Take Home Message—Back pain and issues related to the attaches to the apices of the dorsal spinous processes and is sacroiliac joint region have been well documented as significant often palpable along the dorsal midline. Large and powerful contributors to poor performance in ridden horses. To better trunk muscles are palpable lateral to the thoracolumbar dorsal understand how to manage these challenging issues, a working spinous processes (Fig. 2). The dorsal trunk muscles have knowledge of structural and functional relationships of the caudal variable tonicity, depending on the horse and the amount of thoracolumbar spine, rib cage, abdominal musculature and muscle activity or injury present. sacropelvic is needed. The ribs of the cranial thorax have a nearly vertical orientation; whereas the caudal ribs are more readily palpable and are I. INTRODUCTION angled caudoventrally toward the abdominal region. In ridden horses, the weight of the saddle and rider are carried primarily A thorough understanding of the structure and function of the by the rib cage and less so by the thoracolumbar vertebrae as equine vertebral column can provide a clearer understanding of saddles are designed to provide clearance for movement of the thoracolumbar and pelvic disorders.