Figure 6: A case of brachial plexus birth palsy. MRI in a three-month-old infant at the level of left shoulder joint with drawings to assess GHD. Axial image shows scapular line (yellow) drawn on the body of scapula bisecting the midpoint of the glenoid surface (red line). The alpha angle is subtracted from 90° to get an angle of glenoid version. Humeral head coverage is measured by extending scapular line through the humeral head and a bisecting line drawn at midpoint of the humeral head (green line). The humeral head anterior to scapular line is the percentage of humeral head coverage calculated by the formula: AB/AC X 100%.