All of the following areas are commonly involved sites in pelvic fracture except -

Avulsion fracture of the pelvis are uncommon injuries, seen almost exclusively in adlosescent athletes. These are produced mainly as a result of sudden, forceful or unbalanced contraction of the attached musculo-tendinous unit, while the subject is engaged in a spriting 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. Fracture of the ischial tuberosity is an example of an avulsion fracture and constitues the most uncommon fracture site amongst the options provided. Lateral compression injury (Pubic rami & iliac wing fracture) is the most common injury pattern accounting for 41% of the patients, followed by anteroposterior compression injuries (symphyseal diastasis or longitudinal rami fracture) accounting for 26% and acetabular fractures (18%).