How many ossification centers form the glenoid? How does this relate to glenoid hypoplasia?
The glenoid is formed from 2 ossification centers. Typically, glenoid hypoplasia results from failed formation of the inferior ossification center, causing characteristic deficient posterior glenoid and retroversion.
CT confirms severe scapular neck/glenoid hypoplasia with "dentate" morphology of the glenoid:
- diminished glenoid bone stock (less than 2 cm at the base of the coracoid process), particularly of posterior inferior glenoid
- marked (approximately 30 degrees) of glenoid retroversion
- non-uniform glenohumeral cartilage loss, humeral head and glenoid osteophytosis, and subchondral cyst formation indicate severe osteoarthritis