Definition of two types of anterior superior iliac spine avulsion fractures.

Fractures of the anterior superior iliac spine (ASIS) in adolescents are usually due to avulsion of the sartorius origin from the ASIS; however, the authors here report a second type due to avulsion of the tensor fascia lata origin. Eight patients were identified with ASIS avulsion fractures. Type II sartorius avulsion fracture was due to sprinting in various sports (n = 6). The fragment was smaller and displaced anteriorly. Type II tensor fascia lata avulsion fractures were due to swinging a baseball bat. The two muscular males were both injured during the initial phase of batting. The bony fragment was much larger and displaced laterally as confirmed by three-dimensional computed tomography scans.