This joint is between the tubercle of a rib and the transverse process of a thoracic vertebra. The tubercle of a typical rib has 2 facets.
- Medial facet- articulates with the facet at the tip of transverse process of its own vertebra. Makes synovial joint; covered with hyaline cartilage.
- Lateral facet- non articular facet. Gives attachment to lateral costotransverse ligament.
The costotransverse joints are stabilized by three ligaments.
- Lateral costotransverse ligament.
- Costotransverse ligament.
- Superior costotransverse ligament.
The lateral costotransverse ligament runs from the lateral facet to the tip of the transverse process. The costotransverse ligament is situated between the back of the neck of a rib and front of transverse process. The superior costotransverse ligament passes from the crest on the rib neck to the under surface of the vertebra above. This passes as 2 separate laminae; the anterior and posterior. The anterior lamina is continuous with the posterior intercostal membrane and the posterior lamina is at the plane of external intercostal muscle. Fibres of these laminae lie at right angle to each other, just like the intercostal muscle fibres.
The floating ribs, namely the 11th and 12th ribs don't have tubercles in their neck and thus don't make any synovial joint with the transverse process.