The unique feature of the vertebrae in the thoracic region is the presence of facets, both on the sides of the vertebral bodies and the transverse processes. These are for articulation with the ribs, forming the costovertebral (CV) and costotransverse (CT) joints (Fig. 9.1). Most of the ribs articulate with two adjacent vertebral bodies and one transverse process. The facets on the head of the ribs articulate in turn with demi-facets on the upper and lower borders of the vertebrae, and the crest on the rib head butts onto the intervertebral disc. The joint capsule is loose and strengthened anteriorly to form the three portions of the radiate ligament. The costovertebral joint cavity is divided into two by the intra-articular ligament, except for ribs one, ten, eleven and twelve, which articulate with a single vertebra and have a single joint cavity.