The thoracic spine consists of 12 vertebrae. The sternocostal joints are found between the costal rib cartilage and the sternum. The costovertebral joints are located between the ribs and the vertebral body.
Congenital thoracic kyphosis involves increasing the normal 5 degrees thoracic kyphosis and the anterioposterior curvature of the thoracic spine moves forward. The shoulders round and the head protrudes forward. Adult kyphosis may also involve wedging of the discs, rheumatoid arthritis, osteoporosis, disc thinning or collapse which allows adjacent vertebral bodies to become approximated. The anterior portion of the cartilage plates may be destroyed and bridges of new bones may develop across the intervertebral spaces, resulting in ankylosis. Osteoporosis of the vertebral structures leads to compression fractures of the vertebrae.