Articular capsule of sternoclavicular joint

At a glance

English

Articular capsule of sternoclavicular joint

Latin (TA2)

Capsula articularis articulationis sternoclavicularis

System

Joint

Region

Upper limb

Side

Paired, left and right

About the articular capsule of sternoclavicular joint

The sternoclavicular joint joins the large medial end of the clavicle to the clavicular notch of the manubrium and the upper surface of the first costal cartilage. It is a saddle-type synovial joint, and it is the only bony joint linking the upper limb to the trunk. The articular surfaces are covered by fibrocartilage and are poorly matched, because the end of the clavicle is much larger than the notch it sits in.

The capsule surrounds the joint and is attached around the edges of its articular surfaces, including the margin of the first costal cartilage. Inside, a thick articular disc is fixed to the capsule all round, above and behind to the clavicle and below to the first costal cartilage, dividing the joint into two separate synovial cavities. Outside, the capsule is thickened in front and behind by the anterior and posterior sternoclavicular ligaments. Above, the interclavicular ligament joins the two clavicles across the jugular notch, and below the costoclavicular ligament ties the clavicle to the first rib.

The joint allows the clavicle to rise, fall, move forwards and back and rotate along its long axis, movements that go with every shift of the shoulder. Because the capsule, disc and ligaments are so strong, a fall on the shoulder is far more likely to break the clavicle than to dislocate this joint. When dislocation does occur, it is usually forwards and is easy to see. Backward dislocation is rarer but more serious, as the end of the clavicle can press on the great vessels, trachea or oesophagus behind it.

Attachments and function

Formed by

Margins of the sternal articular surface of the medial end of the clavicle.

Joins

Margins of the clavicular notch of the manubrium and the adjoining first costal cartilage.

Movements

Encloses and strongly stabilises the joint, allowing elevation, depression, protraction, retraction and rotation of the clavicle.

Nerve supply

Medial supraclavicular nerve and the nerve to subclavius.

Blood supply

Branches of the internal thoracic and suprascapular arteries.