Grade Levels I, II and III
Grade I Separation:
- AC ligament may be stretched
- Tenderness when the joint is touched
- Slight pain with arm movement
- Possible bruising
Grade II Separation:
- Partial or complete tearing of AC ligament
- Moderate to severe pain at the joint and with arm movement
- Swelling may be felt on the top of the shoulder where the clavicle ends
- Clavicle may move when pushed
Grade III Separation:
- Separation of the joint
- AC ligament/capsule, coracoclavicular ligaments are damaged
- Individual holds arm close to side while supporting elbow after injury
- Pain persistent in area around joint and ligaments
- Swelling present
- May hear a popping sound with movement
- Shoulder may look deformed and a bump is present on top of shoulder
- AC joint is unstable
Grade IV and VI separations are less common and are the result of a high energy force such as occurs in a motor vehicle or motorcycle accident.
Grade IV: the clavicle is pushed behind the AC joint
Grade V: the muscle attaching to the clavicle is torn is, which causes a significant deformity at the injury site
Grade VI: the clavicle is pushed downward and becomes lodged below the corocoid
