sternocostal

Sternocostal refers to the connections between the sternum and the costal cartilages of the ribs, most notably the sternocostal joints. These joints form the anterior thoracic wall and contribute to chest wall movement during respiration.

Anatomy and joints: There are seven sternocostal joints. The first sternocostal joint, between the manubrium and the first costal cartilage, is typically a primary cartilaginous joint (synchondrosis) that may ossify with age. The joints for ribs 2 through 7 are synovial plane joints between the sternum (manubrium or body) and the corresponding costal cartilages. They are reinforced by radiate sternocostal ligaments and surrounding capsule structures. Occasionally, adjacent costal cartilages form small interchondral articulations (primarily among ribs 8–10), which are separate from the sternocostal joints.

Function and movement: The sternocostal joints allow limited gliding movements, which facilitate chest expansion and recoil during breathing. Their flexibility contributes to the overall mobility of the thoracic cage.

Nerve supply and clinical relevance: The joints receive articular innervation mainly from branches of the adjacent intercostal nerves. Clinically, pain in this region can arise from inflammation or degeneration of the sternocostal joints (sternocostal arthropathy) or from inflammatory conditions of the costal cartilages and related structures. Trauma, arthritis, or costochondral disorders can involve these joints as part of broader chest wall pain syndromes.

Etymology: The term derives from sternum (stern/o) and costa (costal cartilage), reflecting their anatomical relationship in the anterior chest.