Each rib articulates with the thoracic spine through two distinct synovial joints: the costovertebral joint proper (between the rib head and the vertebral bodies) and the costotransverse joint (between the rib tubercle and the transverse process). These two joints act as a functional unit, constraining rib movement to a rotation about an axis connecting the two articular surfaces, which changes orientation from a predominantly anteroposterior axis in the upper thorax (pump handle motion) to a predominantly mediolateral axis in the lower thorax (bucket handle motion).
Costovertebral joint pathology is an underrecognised cause of posterior thoracic pain, often confused with thoracic disc or facet joint pain. Tenderness localised to the costovertebral angle (approximately 3-4 cm lateral to the midline), pain with deep breathing and rotation, and reproduction of pain by rib springing are suggestive. Fluoroscopically guided costovertebral joint injection confirms the diagnosis and provides treatment. The functional axis of the costovertebral joint complex determines the pattern of rib movement with breathing, relevant in respiratory physiotherapy.
Degenerative or inflammatory arthritis of the costovertebral joints produces posterior thoracic pain with a predictable paraspinal and intercostal radiation pattern, worsened by deep inspiration and rotation, managed with physiotherapy, NSAIDs, and joint injection.
The unique single articulation of the first rib with T1 at its costovertebral joint, subjected to repeated pull by the scalene muscles and serratus anterior, predisposes to stress fracture in throwing athletes and military recruits, presenting with posterior and lateral neck pain.
