Sternoclavicular joint
Articulatio sternoclavicularis
Also known as: SC joint
A saddle-type synovial joint, divided by an articular disc, between the medial end of the clavicle and the manubrium and first costal cartilage. It is the only joint connecting the upper limb to the axial skeleton.
Overview
The large medial end of the clavicle articulates with the small clavicular notch of the manubrium and the first costal cartilage. The surfaces are covered with fibrocartilage and are separated by a fibrocartilaginous articular disc, which divides the joint into two compartments and, attached to the upper clavicle and the first costal cartilage, acts as a powerful check against medial displacement of the clavicle. Though anatomically saddle-shaped, the joint functions like a ball-and-socket, allowing elevation and depression, protraction and retraction and axial rotation of the clavicle (≈30–35° of elevation, ≈30° of rotation) — every movement of the scapula involves this joint.
It is extremely strong: the anterior and posterior sternoclavicular ligaments, the interclavicular ligament and especially the costoclavicular ligament (clavicle to first rib — the main stabiliser and pivot) make dislocation uncommon; the clavicle usually fractures first.
- Location
Root of the neck, either side of the jugular notch.
Anatomy
- Innervation
Medial supraclavicular nerve and nerve to subclavius.
- Arterial supply
Internal thoracic and suprascapular arteries.
- Articulations
Sternal end of the clavicle ↔ clavicular notch of the manubrium and 1st costal cartilage (with articular disc).
- Ligaments
Anterior and posterior sternoclavicular ligaments, interclavicular ligament, costoclavicular ligament (strongest).
Function
- Sole bony connection between the upper limb and the axial skeleton
- Allows movements of the clavicle that accompany scapular motion
- Transmits forces from the upper limb to the sternum
Clinical significance
Sternoclavicular dislocation
Anterior dislocation is more common and relatively benign. Posterior dislocation (direct blow to the medial clavicle) is dangerous because the clavicle may compress the trachea, oesophagus, brachiocephalic vessels or subclavian artery — dyspnoea, dysphagia, venous congestion — requiring urgent reduction with a cardiothoracic surgeon available.
Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.