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.
Individual Thoracic Vertebrae. 1  First thoracic vertebrae (T1): Has on either side of the body, an entire articular fact for the head of the first rib, and a demi-facet for the upper half of the head of the second rib. 2  Second thoracic vertebrae (T2): The T2 vertebra is larger than T1 vertebra.