Do all horses have the same number of vertebrae?

Yes, all adult horses have the same number of vertebrae, consisting of 7 cervical vertebrae, 18 thoracic vertebrae, and 6 lumbar vertebrae, followed by 5 sacral vertebrae and between 15 and 24 caudal vertebrae. This totals to 54 to 56 vertebrae in a complete equine spinal column.