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.
The thoracic spine forms the main skeletal support of the back and rib cage (thorax), between the upper, cervical neck and the lower, lumbar spine. Thoracic and related rib pain is a common ailment.he thoracic spine forms the main skeletal support of the back and rib cage (thorax), between the upper, cervical neck and the lower, lumbar spine. Thoracic and related rib pain is a common ailment.