Sternokostala

Sternokostala, or sternocostal joints, are the joints that connect the sternum to the costal cartilages of the first seven ribs, forming a key part of the anterior thoracic cage. The first sternocostal joint lies between the manubrium of the sternum and the first costal cartilage; joints 2 through 7 unite the sternum with the corresponding costal cartilages. The 2–7 joints also include interchondral articulations between adjacent costal cartilages.

The type and structure of these joints vary along their length. The first sternocostal joint is typically a primary cartilaginous joint (a synchondrosis) in which the bones are joined by hyaline cartilage. Joints 2–7 are predominantly synovial plane joints with small gliding movements, stabilized by capsular and extra-articular ligaments. Ligaments associated with the sternocostal region include radiate sternocostal ligaments and sternocostal capsules, with interchondral ligaments linking adjacent costal cartilages in the lower joints.

Functionally, the sternocostal joints contribute to the flexibility of the thoracic cage, allowing subtle movements that accompany respiration. These movements, though small, assist in increasing the volume of the thorax during inhalation and contribute to the mechanics of breathing. They also help transmit mechanical forces between the rib cage and the sternum during activities such as lifting and twisting.

Clinically, sternocostal joints can be involved in pain syndromes or inflammatory conditions, though much chest wall pain more commonly relates to costochondral joints. Trauma, dislocation, or arthritis affecting these joints is relatively uncommon but recognized. Imaging, when indicated, may include CT or MRI for detailed assessment of joint integrity.