Variation in the lumbar spine of the mature ewe: a descriptive study

The purpose of this descriptive study was to characterize the variation in the lumbar spine of the mature ewe. Ventrodorsal and lateral radiographs of the lumbar spine from 216 mature (4-7-year-old) Rambouillet-Columbia cross ewes were examined. Criteria evaluated included the number and orientation of lumbar vertebrae and transverse processes. Observations for fusion of the last lumbar vertebrae with the sacrum and any visible variability seen in transverse processes and ribs were also included. Forty-one percent of the mature ewes had six and 59% had seven lumbar vertebrae. In addition, 7% had abnormal formations at either the first or last lumbar vertebra. Variations seen were the first lumbar vertebra having one rib and one transverse process (7/216, 3%), apparent fusion of the last lumbar vertebra to the sacrum (5/216, 2%) or apparent fusion of one or both of the transverse processes of the last lumbar vertebra to the pelvis (2/216, 1%).