The relationship between the coracoid and glenoid after brachial plexus birth palsy.

The purpose of this study was to determine the changes in glenoid and coracoid anatomy after brachial plexus birth palsy. Fifty-seven children underwent bilateral shoulder magnetic resonance imaging. The uninvolved coracoid angle averaged 32.5 +/- 6.1 degrees (range 21.3-46.0) compared with 21.7 +/- 6.9 degrees (range 6.1-41.0) on the involved shoulder. The uninvolved coracoid physeal angle averaged 42.7 +/- 7.6 degrees (range 26.0-57.0) compared with 61.7 +/- 11.6 degrees (range 38.8-89.9) on the involved shoulder. The uninvolved glenoid physeal angle averaged 78.4 +/- 5.2 degrees (range 66.9-89.9) compared with 50.4 +/- 14.7 degrees (range 17.9-76.7) on the involved shoulder. The uninvolved interphyseal angle averaged 59.6 +/- 7.2 degrees (range 42.0-76.1) compared with 65.5 +/- 11.6 degrees (range 45.0-88.0) on the involved shoulder. The uninvolved coracoid scapular distance averaged 1.6 +/- 0.28 cm (range 1.0-2.5) compared with 1.2 +/- 0.37 cm (range 0.37-1.9) on the involved shoulder. These results highlight the contiguous relationship between the coracoid and glenoid physis during development and indicate that retroversion of both the glenoid and coracoid physis occurs after brachial plexus palsy.