The clavicle

 The clavicle 

The clavicle (collarbone) extends between the manubrium of the sternum and the acromion of the scapula.


It is classed as a long bone and can be palpated along its length. In thin individuals, it is visible under the skin. The clavicle has three main functions:

• Attaches the upper limb to the trunk as part of the ‘shoulder girdle’.

• Protects the underlying neurovascular structures supplying the upper limb.

• Transmits force from the upper limb to the axial skeleton.

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.


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