Representative axial CT image of the affected shoulder from a patient with obstetric brachial plexus injury. Line "a" is the scapular line. Line "b" starts at the most anterior portion of the glenoid labrum and runs tangentially to the most prominent aspect of the coracoid tip. Line "c" represents the glenoid plane. Angle "A" formed between lines "a" and "b" is the coracoscapular angle. C-G represents the distance of coracoid overlap. C-HH represents the coracohumeral distance. C-S represents the coracoscapular distance.