Pediatric Radiology > Musculoskeletal > Trauma > Avulsion Fractures

Avulsion Fractures

Avulsion fractures occur most commonly in adolescent athletes as a result of abnormal stress placed on the tendinous attachments of muscles. Prior to fusion of the ossification centers, the growing apophysis is more likely to become injured than the adjoined tendons. The most common sites of avulsion occur in the pelvis where the muscles with the greatest strength are attached.

The most common locations:

  • iliac crest: transversalis, internal oblique and external oblique muscles
  • anterior superior iliac spine: sartorius muscle
  • anterior inferior iliac spine: rectus femoris muscle
  • ischial tuberosity: hamstring muscles (biceps femoris, gracilis, semimembranosus and semitendinosus)
  • lesser trochanter: iliopsoas muscle
Avulsion injury of the right ischial tuberosity in a 14-year-old boy. Radiograph shows lateral displacement of a right ischial tuberosity fragment (arrow) likely secondary to an avulsion fracture involving the biceps femoris.


Avulsion type fracture of right anterior inferior iliac spine in a 14-year-old male sprinter. Left, AP view of right hip reveals bony fragmentation inferior to the iliac spine and lateral to the femoral head. Right, Coronal MR through pelvis shows increased signal in the right anterior inferior iliac spine at the site of insertion of the rectus femoris muscle, consistent with an avulsion fracture.

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