From the Guidelines
The joint at the sternum and the ribs is called the costosternal joint or chondrosternal joint, which refers to the transition between the costal cartilage and the sternum 1.
Key Points
- The costosternal joint is a crucial anatomical location for rib fractures, as it can affect the stability of the chest wall and the prognosis of thoracic trauma patients.
- The exact point of fracture at the costosternal joint should be described as “Chondro-sternal junction” to specify the transition between the cartilage and sternum 1.
- Fractures within 2.5 cm of the costal cartilage may be repaired by spanning plates to the sternum outer cortex if possible, or alternatively by fixation to the cartilage 1.
- The costosternal joint is an important consideration in surgical stabilization of rib fractures (SSRF), as it can impact the choice of surgical approach and technique 1.
Anatomical Location
The costosternal joint is located at the anterior aspect of the thorax, where the costal cartilage meets the sternum.
- The costal cartilage is a flexible, cartilaginous structure that connects the ribs to the sternum.
- The sternum is a flat, elongated bone that forms the center of the chest wall.
- The costosternal joint is a synovial joint that allows for limited movement between the costal cartilage and the sternum.
From the Research
Joint at the Sternum and the Ribs
The joint at the sternum and the ribs is referred to as the sternocostal joint or costosternal joint. This joint is formed by the articulation of the costal cartilage of the ribs with the sternum.
Types of Sternocostal Joints
There are different types of sternocostal joints, including:
- Synchondrosis: a type of cartilaginous joint where the costal cartilage of the first rib articulates with the manubrium of the sternum 2
- Synovial joint: a type of joint where the costal cartilage of the second rib articulates with the sternum, allowing for more movement 2
- Interchondral joints: joints between the costal cartilages of adjacent ribs, which can vary in presence and morphology 3, 4
Characteristics of Sternocostal Joints
The sternocostal joints have several characteristics, including:
- The first sternocostal joint is either a synchondrosis or synostosis, while the second sternocostal joint is a synovial joint 2
- The presence of interchondral joints between ribs 4/5/6/7, and 7/8 can vary, with some individuals having more or fewer of these joints 3, 4
- The costal cartilages of the ribs can form a common cartilage via cartilaginous unions, which can also vary between individuals 4
Variability of Sternocostal Joints
There is significant variability in the anatomy of the sternocostal joints and the costal margin, with different studies finding different frequencies of interchondral joints and costal cartilage morphology 3, 4. This variability is important for chest wall surgeons to appreciate when treating diseases of the costal margin.