The thoracic spine (upper back) is a very stable area of the body with little motion because it is attached to the ribs and breastbone. The rib joints that connect each rib to the second through the tenth vertebrae in the upper back are called costotransverse and costovertebral joints. These joints provide stability to the upper back and chest wall. The joints are supported by ligaments, which add strength to the junction of bones and limit the motion of the joints in the upper back.
Any abnormal motion or dysfunction with these joints can lead to upper back pain. The source of the pain is usually diagnosed with a costovertebral joint injection.