The phylum Chordata is a taxonomic group. All animals which have a  spine, or backbone, are classified in the phylum Chordata. There  are three subphylums in Chordata: Uroch â¦ ordata (tunicates),  Cephalachordata (lancelets), and Vertebrata (vertebrates).
The 12 vertebrae in the upper back make up what is known as the thoracic spine. They curve outward and inward to provide structure for the rib cage. The bones provide structure and flexibility for the body, while protecting the spinal colu... Read More.
All the thoracic vertebrae-all 12 have ribs attached. The curve the thoracic spine has is call â¦ ed the thoracic curve, or kyphosis. It is normal to have a curve but if the curve is excessive or twists to the side it is abnormal. It can cause problems or if mild most people do not know it is there.