Anatomical landmarks for acetabular abduction in adult hips: the teardrop vs. the inferior acetabular rim

ConclusionsAAD measurements considering the inferior acetabular rim can be more accurate than those considering the acetabular teardrop because the inferior rim represents the nearly hemispheric acetabulum better than does the teardrop. It is recommended to differentiate between the teardrop and the inferior acetabular rim when measuring AAD to avoid confusion regarding acetabular abduction.
Source: Surgical and Radiologic Anatomy - Category: Anatomy Source Type: research