Shoulder AC Joint X-ray (both sides)

What it is

The acromioclavicular joint is the bump you can feel on the top of your shoulder, where the outer end of the collarbone meets the highest point of the shoulder blade. It is held together by ligaments, and when those ligaments tear — most often from landing directly on the shoulder — the collarbone end rides upward. The question an x-ray is asked here is how far it has moved, and that is a comparison, not an absolute: this study images both acromioclavicular joints so the injured side can be held against the patient's own normal one.

The weighted part is a way of provoking the finding. A ligament that is stretched or partly torn can look nearly normal with the arm hanging free, but hold a weight in the hand and gravity pulls the arm and shoulder blade down while the collarbone stays put, opening the gap. The code covers the study whether or not weights are used, so the same code is billed either way.

Why it is done

• To confirm a separated shoulder after a fall onto the shoulder, and to judge how severe the separation is
• To distinguish a separation of this joint from a broken collarbone or a dislocation of the main shoulder joint, which are different injuries treated differently
• To make a borderline injury visible, when the arm-hanging view is equivocal and the weighted view is not
• To assess arthritis or bone changes at the joint in someone with pain localized to the top of the shoulder

What to expect

You will usually be imaged standing or sitting upright with both shoulders in the field. If weights are used, they are held in the hands or strapped to the wrists rather than gripped, so the shoulder muscles stay relaxed — tensing them defeats the test. Holding a weight on a freshly injured shoulder can hurt, and it is reasonable to say so; the images may be taken without weights first. Each exposure lasts an instant and the visit is short. The degree of separation graded on these films is a large part of what determines whether treatment is a sling or an operation.

Questions worth asking

• Is this billed once for both shoulders, or as two separate studies?
• Are the weighted views billed on top of the standard ones, or is it all one charge?
• If this is being done in an emergency department, what is the facility level charge on top of the imaging itself?
• Will the orthopedic surgeon I am referred to accept these images, or do they typically repeat them in their own office?