South Wales Osteopathic Society

This small joint lies at the tip of the shoulder, joining the clavicle (collar bone) to the shoulder blade. The clavicle  acts as a strut to keep the shoulder blade from rolling in toward the breast bone. It also gives attachment for the muscles at the front of the neck and the chest. The acromio-clavicular joint moves as you move your arm, particularly toward the end of abduction (the movement of taking the arm out from the side)

The main  conditions to which the joint is subject are strain, subluxation and osteoarthritis. With a strain the capsule (the tough outer bag of the joint) and ligaments are  forced excessively, such as in a fall, causing minor tears in their fibres. The injury is graded according to severity. Depending on the amount of damage in the initial stages the joint may need support and ice packing. As the capsule and ligaments heal, adhesions can form , limiting joint movement. This can lead to pain in the joint that persists longer than none would expect healing to occur.  Osteopathic treatment to mobilise the joint can help here.

Subluxation  means partial dislocation. It results from a heavy impact downward on the shoulder such as in a rugby tackle. The patient is left with a characteristic “step” in the shoulder. There is no loss of function , it is merely cosmetic and needs no treatment.

Osteoarthritis  in the joint can occur, giving local pain over the tip of the shoulder, exacerbated by certain movements, such as bringing the arm fully across the chest. Some times a bony spur forms on the under surface of the joint. This can dig painfully into the underlying tendon of the supraspinatus muscle. Ostepathic mobilisation of the joint, while not reducing the osteoarthritis itself, can free the joints movement and reduce symptoms.

It is important when examining the joint to also assess the other end of the clavicle, where it joins the breast bone – the sterno-clavicular joint. Movement restriction here can affect the mechanics of the acromio-clavicular joint and will benefit from osteopathic attention.