What is an AC Separation?
When the AC joint is “separated” it means that the ligaments connecting the acromion and clavicle have been damaged, and the two structures no longer line up correctly. AC separations can be anywhere from mild to severe, and AC separations are “graded” depending upon which ligaments are torn and how badly they are torn. Grade I Injury – the least damage is done, and the AC joint still lines up. Grade II Injury – damage to the ligaments which reinforce the AC joint. In a grade II injury these ligaments are only stretched but not entirely torn. When stressed, the AC joint becomes painful and unstable. Grade III Injury – AC and secondary ligaments are completely torn and the collarbone is no longer tethered to the shoulder blade, resulting in a visible deformity.
