Into the composition of the thoracic portion of the skeleton, enter the sternum and ribs, which are proper and peculiar to it, and the Vertebrae, which are common to it and other parts.

A  lateral external anterior view of the thorax. c. The superior piece ofthe sternum. d. The middle piece. f. The inferior piece, or ensiform cartilage. 1d. The first dorsal vertebra. 12c. The last dorsal vertebra. c1. The first rib.