Hill-Sachs defect

• Hill-Sachs defects are a posterolateral humeral head depression fracture, resulting from the impaction with the anterior glenoid rim, and indicative of an anterior glenohumeral dislocation. It is often associated with a Bankart lesion of the glenoid.

CT and MRI

• loss of the normal circular shape in the posterolateral region of the superior humeral head on axial images
• MRI and CT will show smaller defects
• anatomic shape can be preserved but the presence of bone marrow oedema in the posterolateral humeral head indicates an acute injury
• normal flattening of the posterolateral humeral head caudal to the level of coracoid should not be misinterpreted as a Hill-Sachs defect (sometimes termed pseudo-Hill-Sachs defect)