The Clavicle

Bony Landmarks and Articulations

The clavicle is a slender bone with an ‘S’ shape. Facing forward, the medial aspect is convex, and the lateral aspect concave. It can be divided into a sternal end, a shaft and an acromial end.

Sternal (medial) End

The sternal end contains a large facet – for articulation with the manubrium of the sternum at the sternoclavicular joint.

The inferior surface of the sternal end is marked by a rough oval depression for the costoclavicular ligament (a ligament of the SC joint).

Shaft

The shaft of the clavicle acts a point of origin and attachment for several muscles – deltoid, trapezius, subclavius, pectoralis major, sternocleidomastoid and sternohyoid

Acromial (lateral) End

The acromial end houses a small facet for articulation with the acromion of the scapula at the acromioclavicular joint. It also serves as an attachment point for two ligaments:

• Conoid tubercle – attachment point of the conoid ligament, the medial part of the coracoclavicular ligament.
• Trapezoid line – attachment point of the trapezoid ligament, the lateral part of the coracoclavicular ligament.

The coracoclavicular ligament is a very strong structure, effectively suspending the weight of the upper limb from the clavicle.

By TeachMeSeries Ltd (2025)

Fig 2
Bony landmarks of the inferior surface of the clavicle.

Clinical Relevance

Fracture of the Clavicle

The clavicle acts to transmit forces from the upper limb to the axial skeleton. Given its relative size, this leaves it particularly susceptible to fracture. The most common mechanism of injury is a fall onto the shoulder or onto an outstretched hand.

With the clavicle arbitrarily divided into thirds:

• 15% of fractures occur in the lateral third
• 80% occur in the middle third
• 5% occur in the medial third.

After a fracture, the lateral end of the clavicle is displaced inferiorly by the weight of the arm and displaced medially by the pectoralis major. The medial end is pulled superiorly by the sternocleidomastoid muscle.

Management of a clavicular fracture can be conservative (e.g. sling immobilisation) or operative (e.g. open reduction and internal fixation). The supraclavicular nerves lie in close proximity to the clavicle and are occasionally sacrificed during a surgical repair – resulting in a numb patch over the upper chest and shoulder.

By TeachMeSeries Ltd (2025)

Fig 3
X-Ray of a clavicular fracture. Note how the medial end is raised and the lateral end lowered