ACROMIOCLAVICULAR (AC) SPRAIN / SEPARATION
The acromioclavicular joint (AC) is found on the top of the shoulder and is located between the collar bone and part of the shoulder blade defined as the acromion. Through this articulation, the collar bone can act as a strut, maintaining the upper limb away from the thoracic cage and thus permitting a greater range of upper limb motion. The AC joint is supported by the acromioclavicular, coracoacromial ligament and coracoclavicular ligament.
Traumatic injury to the acromioclavicular joint whether secondary to a fall onto the point of the shoulder, impaction to the front of the collar bone or a fall onto an outstretched hand, can lead to stretching of the ligaments which support the acromioclavicular joint and a subsequent sprain.
As with any acute sprains, the patient will report pain and swelling. The pain is usually located over the front or top of the shoulder directly over the AC joint and there is often pain with overhead activities and downward pressure on the injured arm. As you can see on the image below of the right shoulder, there may also be a step deformity illustrating disruption of the AC joint.
Prior to commencing treatment, it is important to stage the extent of injury so that the most appropriate treatment can be initiated. There are three separate grading systems (Yochum and Rowe, 1996):
|Severity||Acromioclavicular ligament||Coracoclavicular ligament||X-ray findings|
|Moderate||Disrupted||Stretched||Wide joint space and slight clavicle elevation|
|Severe||Disrupted||Disrupted||Wide joint space and severe clavicle elevation|
(The list of conditions given above and subsequent explanations are intended as a general guide and should not be considered a replacement for a full medical examination. Furthermore, we do not purport to treat all the conditions listed. Should you wish to discuss any of these conditions with our chiropractors, please do not hesitate to phone the clinic on 020 7374 2272 or email firstname.lastname@example.org).