Acromioclavicular joint

• The distal end of the clavicle meets the acromion process of the scapula to form the Acromioclavicular joint. A plane synovial joint, the AC joint allows a gliding articulation between the acromion and the clavicle, capable of 3 degrees of freedom of movement, each around an oblique axis:

• Internal and external rotation around a vertical axis,

• Upward and downward rotation around an axis perpendicular to the plane of the scapula,

• Anterior and posterior scapular tilting around a horizontal axis.

• This articulation allows for the motion necessary to maintain the relationship between the scapula and the clavicle in the early and late stages of the GH joint’s ROM