Acromioclavicular (AC) Shear Test: How to Check for AC Joint Sprain

The Acromioclavicular (AC) Shear Test, also known as the AC Joint Compression Test, is a key special test used to assess the integrity of the acromioclavicular joint. Click the sections below for details on how to perform it.

1. Purpose

The primary purpose of the AC Shear Test is to **test for** pathology of the Acromioclavicular (AC) joint. This includes AC joint sprains (separation) or arthritis. The test works by compressing the joint, which provokes pain if it is injured.

2. How to Perform

1. The patient is positioned in sitting, with their arms relaxed at their sides.
2. The examiner stands beside or slightly behind the affected shoulder.
3. The examiner cups their hands over the shoulder, placing the heel of one hand on the anterior clavicle.
4. The examiner places the heel of the other hand on the spine of the scapula.
5. The examiner then slowly and firmly squeezes their hands together, applying a compressive (shear) force directly to the AC joint.

3. Positive & Negative Sign

Positive Sign (Test is POSITIVE):
A positive test (indicating AC joint pathology) is:

• Reproduction of pain located at the AC joint as the pressure is applied.
• Abnormal movement or a "popping" sensation at the joint may also be noted.

Negative Sign (Test is NEGATIVE):
A negative test is the absence of pain or abnormal movement at the AC joint during compression.