Shoulder Case 8 Diagnosis
AC Separation
Diagnosis
Standard radiographs of the shoulder should be obtained (AP, scapular Y view). The normal AC joint space is 3mm and the normal coracoclavicular distance is 13 mm. Anything larger than these are pathologic. There are six types of AC separations:
Type I:
- AC sprain, tender over AC joint
- X Ray: normal
Type II:
- Torn AC ligament, stretched CC ligament
- X Ray: slight increase AC distance
Type III:
- Torn AC and CC ligaments
- X Ray: clavicle elevated above the normal plane of AC joint (>5mm), increased CC distance (>13 mm)
Type IV:
- Torn AC and CC ligaments, displaced clavicle into trapezius
- X Ray: distal clavicle is displaced posteriorly
Type V:
- Torn AC and CC ligaments, muscular disruption of attachments to distal clavicle
- X Ray: elevated clavicle above acromion (up to 1-3 x width of clavicle), CC distance 3 times normal
Type VI:
- Torn AC and CC ligmaments, complete muscular disruption
- X Ray: complete disruption of joint (displacements beyond Type V parameters)