Which structure does the supraspinatus muscle run under in a positive Hawkins-Kennedy test?

The supraspinatus muscle runs under the coracoacromial arch in a positive Hawkins-Kennedy test. This test is specifically designed to assess for impingement of the supraspinatus tendon, which is one of the key components of the rotator cuff.

The coracoacromial arch is formed by the coracoacromial ligament, which connects the coracoid process of the scapula to the acromion. This arch functions as a roof over the subacromial space, where the supraspinatus tendon passes. When conducting the Hawkins-Kennedy test, the shoulder is brought into a position that compresses the supraspinatus tendon beneath this arch. If there is impingement, pain or discomfort is typically elicited, indicating potential issues with the supraspinatus or surrounding structures.

Understanding the anatomy involved helps clarify why the coracoacromial arch is critical in this context, as it plays a direct role in the mechanism being tested.