The document describes the anatomy of the thoracic, lumbar, sacrum, and coccyx regions of the spine. It notes that the thoracic region contains 12 vertebrae that connect to pairs of ribs. It describes facets on each thoracic vertebra for articulation with ribs. The lumbar region contains 5 vertebrae, which are the largest as they bear most of the weight of the upper body. The sacrum lies below the lumbar region and fuses several vertebrae into a triangular shape. It has articulation surfaces and foramina. The coccyx is made of 4 vertebrae fused together at the bottom of the spine forming the tailbone. It artic