Anterior sternoclavicular ligament

At a glance

English

Anterior sternoclavicular ligament

Latin (TA2)

Ligamentum sternoclaviculare anterius

System

Ligament

Region

Upper limb

Side

Paired, left and right

About the anterior sternoclavicular ligament

The sternoclavicular joint is the only true joint linking the upper limb to the trunk. The enlarged medial end of the clavicle sits in a shallow notch on the upper corner of the manubrium and the first costal cartilage, with an articular disc between them that divides the cavity into two. Because the bony surfaces fit poorly, the joint relies on a strong capsule and a set of ligaments, and the anterior sternoclavicular ligament is the thickening of the capsule on its front.

It is a wide, flat sheet of fibres. Above, it is fixed to the clavicle's inner end, on its front and upper surface; its fibres then slope down and inwards across the front of the joint to the anterior surface of the manubrium near its upper border. Superficially it is covered by the sternal head of sternocleidomastoid and by skin, and it can be felt beneath the skin on either side of the jugular notch. Deep to it lie the joint capsule, the articular disc and the two synovial compartments. Its partners are the posterior sternoclavicular ligament behind, the interclavicular ligament above and the costoclavicular ligament below.

The ligament limits forward movement of the medial end of the clavicle, as happens when the shoulder is drawn backwards, and helps keep the joint surfaces in contact during the wide movements the clavicle makes as the arm is raised.

Sternoclavicular dislocation is uncommon because the joint is so well bound, but when it occurs the clavicle usually moves forwards, tearing this ligament; the medial end then makes a visible bump and the joint is often treated without surgery. Backward dislocation is rarer and more dangerous, because the great vessels and the trachea lie behind the joint. In young adults an apparent dislocation may instead be a growth plate injury, since the medial clavicular epiphysis is the last in the body to fuse.

Attachments and function

Attaches from

The front and top of the clavicle's medial end.

Attaches to

The anterior surface of the manubrium of the sternum near its upper border.

Function

Reinforces the front of the sternoclavicular joint capsule and limits forward displacement of the medial end of the clavicle.

Nerve supply

Branches of the medial supraclavicular nerve and the nerve to subclavius.

Blood supply

Branches of the internal thoracic and suprascapular arteries.