Avulsion fractures of apophyses and spines of the pelvis are usually considered uncommon injuries, seen almost exclusively in adolescent athletes mainly as a result of the sudden, forceful or unbalanced contraction of the attached musculo-tendinous unit, while the subject is engaged in a sporting event such as kicking a ball, running or jumping.

These fractures usually are related to the time of ossification nuclei appearance and their fusion to the corresponding pelvic tuberosities. In acute injuries, the athletes experiences sudden, shooting pain referred to the involved tuberosity and loss of muscular function; swelling and local tenderness can be appreciated by palpation and evoked during movements passively imposed upon the appropriate limb.

The diagnosis, suggested by physical findings, symptoms, patient's age and biomechanical analysis of the accident, is confirmed by radiographs.

Common pelvic avulsion sites and associated muscle tendon insertions are as follows:

Anterior inferior iliac spine - rectus femoris
Anterior superior iliac spine - sartorius
Iliac crest - abdominal muscle
Greater trochanter - gluteal muscles
Lesser trochanter - iliopsoas
Symphysis - adductor group
Ischial tuberosity - hamstrings

Reports of isolated cases are common in the literature while few large series of pelvic avulsion fractures are reported. In 1981 Fernbach and Wilkinson reviewed 20 cases of avulsion fractures of the pelvis and proximal femur most of which occurred in male adolescents engaged in active sports. In 1985 Metzmaker and Pappas studied 27 cases of avulsion fractures of the pelvis finding that the areas of injury included the Anterior Superior Iliac Spine in 11 cases, the Ischium in 6 cases, the Anterior Inferior Iliac Spine in 4 cases, the Lesser Trochanter and the Iliac Crest in 3 cases.  In 1994 Sundar and Carty identified 32 avulsion fractures in 25 patients participants in sports with eight instances of multiple avulsions; the sites of injuries were ischial tuberosity (17 cases), Anterior Inferior Iliac Spine (8 cases) and Anterior Superior Iliac Spine (7 cases).

In a recent large retrospective study by Rossi & Dragoni, two hundred and three acute apophyseal avulsion fractures (16.4%) were identified in 198 adolescent athletes where frequency and intensity of sport participation were constant. The gymnasts observed were all classified as "top level athletes" and the lesions predominantly documented among females.  In five cases, four of whom were engaged in soccer and one in athletics, multiple avulsions were present located in the Ischial Tuberosity (IT) in addition in the Anterior Inferior Iliac Spine (AIIS).  The average age was 13.8 years with a range of 11 to 17 years; all injuries were sports induced with a different distribution which was related to the sport involved.  There were 139 males (68.5%) and 64 females (31.5%).

The location of the 203 cases were: IT 109, AIIS 45, (ASIS) 39, superior corner of pubic symphysis 7 and IC 3.  The distribution with regard to the athletic activity undertaken reveals that soccer and gymnastics were mainly responsible for the IT lesions; soccer, athletics and tennis for AIIS lesions; soccer, athletics and gymnastics for ASIS lesions  and soccer and fencing for SCPS lesions. The three cases of IC avulsion were in soccer, gymnastics and tennis.