Ilium fractures are mostly comminuted and caused by direct blow to the lateral pelvis or vertical shear.
Fractures of the ilium that extend over the pelvic brim are usually combined with anterior pelvic injuries and are highly instable.
Great care should be taken to differentiate ilium fractures from stable horizontal fractures of the iliac wing which do not compromise pelvic ring stability. The latter is dealt with in a separate section.
All of these injuries should be addressed together with any other injury to the pelvic ring.