Acromioclavicular joint

The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle.

Related Topics:
Joint - Shoulder - Acromion - Scapula - Clavicle

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The joint is stabilized by three ligaments: The acromioclavicular ligament, the coracoclavicular ligament, and the capsule ligament.

Related Topics:
Ligament - Acromioclavicular ligament - Coracoclavicular ligament - Capsule ligament

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

A common injury to the AC joint is dislocation, or AC shoulder separation. This occurs often in sports like football, soccer, horseback riding, mountain biking, and biking. The dislocation is classified on a scale of 1 to 6, with 6 being the most severe. A type one AC dislocation invovles trauma to the ligaments that form the joint, but no severe tearing or fracture. It is commonly referred to as a sprain. Most doctors treat this type of dislocation with anti-inflamatory drugs and the placement of the arm in a sling.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

A type 2 AC dislocation involves tearing of the ligaments, which causes a noticeable bump on the the shoulder. Severe pain and loss of movement are common. Treatment is typically an arm sliing, bed rest, and anti-inflamatory drugs. Most people recover full motion of the shoulder and arm within 6 to 8 weeks, often with the assistance of physical therapy.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

More severe and less treatable are type 3 through 6 separations. These involve the complete tearing of the ligaments at the AC joint and those under the scapula that hold the shoulder in place, and the clavicle bone left floating. A significant bump appears and movement may be very retricted. Pain can be very severe in these instances. Many doctors will not do surgery on a type 3 separation as it is debatable how effective the surgery is. The most common surgery is the Weaver-Dunn, which involves the grafting of tendons and muscles from the leg. Variations include the use of synthetic sutures to assist in the strengthening of the grafts. Type 4 through 6 separations always result in surgery. The Weaver-Dunn procedure is 50% successful, with the best results in males (females tend to have more clavicle breakage after the surgery). Physical therapy is always recommended after surgery, and most patients get flexibility back, although somewhat limited.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~