Bones - Clavicle Flashcards
Where is the clavicle located?
What type of bone is it?
It is located between the manubrium of the sternum and the acromion of the scapula.
It is classified as a long bone.
What are the functions of the clavicle?
1) Attaches the upper limb to the trunk as part of the ‘shoulder girdle’.
2) Protects the underlying neurovascular structures supplying the upper limb.
3) Trasmits force from the upper limb to the axial skeleton.
What is the shape of the clavicle?
It is ‘S-shaped’ and can be divided into the sternal end, a shaft and an acromial end.
Sternal end of the clavicle
Bony landmarks?
Associated ligament?
1) Large facet - articulation with the manubrium of the sternum at the sternoclavicular joint.
2) Rough oval depression (inferior surface) - for the costoclavicular ligament (a ligament for the SC joint)
Shaft (body) of the clavicle
Muscle attachments of the clavicle?
Acts as a point of origin and attachment for several muscles:
1) Deltoid
2) Trapezius
3) Subclavius
4) Pectoralis major
5) Sternocleidomastoid
6) Sternohyoid
Acromial end of the clavicle
Bony tubercles?
Associated ligaments?
1) Small facet - articulation with the acromion of the scapula at the acromioclavicular joint. It also serves as an attachment point for two ligaments:
i) Conoid tubercle - attachment point of the conoid ligament the medial part of the coracoclavicular ligament.
2) 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 weight of the upper limb from the clavicle.
Clinical relevance: Fracture of the Clavicle
Aetiology or mechanism?
Types?
Treatment?
Acts to transmit forces from the upper limb to the axial skeleton.
Given its relative size, it is particularly susceptible to fracture.
Most common mechanism of injury is falling onto the shoulder or an outstreched hand.
Most fractures occur in the middle third. After fracture, the lateral end 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 the fracture is conservative (e.g. sling immobilisation) or operative (e.g. open reduction and internal fixation, ORIF). In ORIF, the supraclavicular nerves are often sacrificed - resulting in a post-operative numb patch over the shoulder.
