Northwestern University Feinberg School of Medicine

Orthopedic Teaching

Pediatrics Case 1 Diagnosis

Avulsion Fracture of the Anterior Superior Iliac Spine


Diagnosis is typically made by AP pelvis radiographs. Axial and oblique views of the pelvis may also reveal the fracture.

An AIIS avulsion may resemble the os acetabuli, a normal secondary ossification center at the superior lateral margin of the acetabulum. Clinical findings of pain, swelling, and limited range of motion helps distinguish the avulsion injury from the normal variant.