Radiographic Features of the Normal Equine Thoracolumbar Spine

Abstract

The normal radiographic anatomy of the equine thoracolumbar (TL) spine is described from birth to maturity. Closure of the vertebral epiphyses was found to take place from 30 to 38 months of age. In a series of 110 normal horses, there were few incidental radiologic abnormalities seen apart from changes associated with crowding and overriding of the dorsal spinous processes. Sixty‐six percent of horses were free from any detectable radiologic lesion, and an additional 12 percent showed only impingement of the dorsal tips of one or more summits. The remainder (22 percent) exhibited some evidence of overriding of the dorsal spinous processes, but in only 3 percent were the changes pronounced. This reduction or obliteration of the normal interspinous spaces occurred chiefly in the midback from T13 to T18 and was associated with pressure points between adjacent spines with local periosteal reaction and focal areas of radiolucency. The tips of the processes sometimes overlapped one another and became misshapen, presumably as a result of continued pressure from the adjacent impinging spines.