• The acromiclavicular joint (ACJ) is situated betwen the collar bone (clavicle) and part of the shoulder blade (acromion).
• Pain from the ACJ can occur for a variety of reasons.
• Pain is typically localised to the region of the joint.
• Treatment may require a localised injection, surgery, or both.

Where is the acromioclavicular joint (ACJ) ?

The acromioclavicular Joint (ACJ)

The acromioclavicular joint (also abbreviated to the ACJ) is the joint at the top of the shoulder lying between the outer end of the collar bone (clavicle) and the upper portion of the shoulder blade (acromion). The ACJ and sternoclavicular joints (SCJ) are key links between the arm and central skeleton. The ACJ is reinforced by strong ligaments (the coracoclavicular ligaments) that run from part of the shoulder blade (known as the coracoid) to the collar bone.

What type of conditions affect the ACJ ?

The ACJ can be damaged by trauma, infection (rarely), inflammatory and degenerative disease.

X-ray of a normal acromioclavicular joint

Disruption of the ACJ

X-ray of an arthritic ACJ

MRI showing ACJ degenerative changes

In many cases of degenerative disease there may be a background of previous trauma or a heavy manual occupation.

What symptoms arise from the ACJ?

Symptoms from the acromioclavicular include pain and instability of the joint. Pain from the ACJ is commonly located on the point of the shoulder.