A, Superior segmental defect violates superior supporting rim and part of anterior supporting rim of acetabulum. B, Medial segmental defect violates medial supporting rim. C, Three cavitary defects involve excavation of bone without violation of superior, posterior, or anterior rim. D, Medial cavitary. Excavation of medial wall of acetabulum occurred without violation of medial rim (contained bone defect). E, Combined segmental cavitary defects. Superior, anterior segmental lesion combined with superior, anterior, and medial cavitary defects. F, Pelvic discontinuity. Interruption of anterior and posterior columns creates rare but unstable defect. G, Arthrodesis. Acetabular cavity filled with bone.