Sternoclavicular Joint

Question 1

Articulating surfaces

Answer 1

Sternal end of clavicle
Manubrium of sternum
Part of 1st costal cartilage

Question 2

Joint capsule

Answer 2

Fibrous outer layer - extends from epiphysis of sternal end of clavicle to borders of articular surfaces and articular disc
Inner synovial membrane - reduce friction in joint

Question 3

Ligaments

Answer 3

Sternoclavicular ligaments (ant. + post.) - strengthen joint capsule ant. and post. 
Interclavicular ligament - spans gap between sternal ends of each clavicle and reinforces joint capsule superiorly
Costoclavicular ligament - two parts (often separated by a bursa) bind at the 1st rib and cartilage inferiorly and the anterior and posterior borders of the clavicle superiorly (main stabilising force of joint, resisting elevation of pectoral girdle)

Question 4

Neurovascular supply

Answer 4

Internal thoracic artery
Suprascapular artery
Medial supraclavicualr nerve (C3/4)
Nerve to the subclavius (C5/6)

Question 5

Movements

Answer 5

Elevation of shoulders 
Depression of shoulders 
Protraction of shoulders 
Retraction of shoulders 
Rotation

Question 6

Mobility and stability

Answer 6

Mobility - saddle joint - can move in two axes / articular disc - allows clavicle and manubrium to slide over one another more freely allowing movement in 3rd axis
Stability - strong joint capsule / strong ligaments

Question 7

Dislocation

Answer 7

Quite rare - requires significant force
Anterior dislocation - more common, can happen following blow to anterior shoulder
Posterior dislocation - force driving shoulder forward or direct impact to the joint

In younger people the epiphyseal growth plate of the sternal end of the clavicle not fully closed - dislocation accompanied by fracture through plate