I got to spend the morning observing surgery with Dr. Dillingham and Dr. Donahue from SOAR Medical. Definitely a great experience to watch 2 of the best surgeons at work.
Subacromial decompression and a release of the coraco-acromial ligament are common procedures used to relieve shoulder impingement after conservative treatment has not resolved the problem.
“the site of contact between the humeral head and coraco-acromial arch may deserve to be viewed as a neo-articulation that developed during evolution to compensate for the relative weakness of the supraspinatus muscle in humans. This neo-articulation is poorly suited to the current long lifespan of humans, which is the result of cultural developments, as opposed to evolution. Its existence may contribute to explain the high prevalence of rotator cuff tendon disorders in humans.”
Summary: We have a coraco-acromial ligament due to our deltoid being much stronger than our rotator cuff muscles (primarily suprapinatus). Strengthening the rotator cuff and lessening the discrepancy in strength compared to the deltoid is essential to decrease increased articulation of the shoulder with the coraco-acromial ligament and would decrease shoulder impingement.
Evolutionary bio article explaining the shoulder’s evolution: http://www.sciencedirect.com/science/article/pii/S1877056814002473