Fractures and Dislocations of the Pelvis

Fractures and Dislocations of the
Sacral Fractures
• Usually from fall or direct trauma; 2 types:
• Horizontal(transverse) fxs.- m.c. type; m.c. levels are S3 and S4
– AP view shows disruption of foramina
– Lateral shows disruption of anterior cortex and possible angulation or displaced
distal fragment
• Vertical fractures- result from indirect pelvic trauma
– AP may show asymmetry of foramina
– Not visible on lateral
Coccygeal Fractures
• Usually transversely oriented
• Best seen on lateral view
– May show angulation or
anterior displacement of
distal fragment
Fractures of the Ilium
• Iliac wing fxs.- AKA Duverney fx.; splitting of iliac wing from
direct lateral trauma
• Malgaine's fx.- double injury; ipsilateral double vertical fracture of the
superior pubic ramus and ischiopubic ramus, with fracture or dislocation
of the sacroiliac joint
Fractures of the Ilium
Acetabular fractures: Resulting acetabular injury depends on position of femur at
the moment of impact
-4 types
-Posterior rim fracture (dashboard fracture)- occurs after a
blow to the knee while the leg is flexed and adducted
(1/3 of acetabular fxs.)
-Simple posterior column fx- uncommon
-Central acetabular fx. (explosion fx.)- m.c. acetabular fx;
divides innominate bone into superior and inferior halves
-Simple anterior column fx- on AP, there is loss of
continuity of the iliopubic line
Fractures of the Ilium
• Avulsion fractures- more common in adolescents at
apophyses before fusion of the involved growth centers;
more common in athletes
– ASIS- avulsed by sartorius muscle
– AIIS- avulsed by avulsed by rectus
femoris muscle
Pubis and Ischium Fractures
• Straddle fx.- m.c. type of unstable pelvis fx.
– Double vertical fracture that involves both
superior pubic rami and ischiopubic junctions
– Fragments may rupture the bladder
Pubis and Ischium Fractures
• Avulsion fractures:
– Symphysis pubis- avulsion by major adductor muscles
at superior or inferior pubic rami near pubic
– Ischial tuberosity (rider’s bone)- avulsion by hamstring
• Frequently bilateral
• Fragment may show
overgrowth over time and
get mistaken for osteochondroma
Pelvic Dislocations
• Sprung pelvis- represents complete separation
of the symphysis pubis and one or both of the
SI joints (pelvis looks like an open book)
– Severe pelvic basin
visceral damage may
Pubic Diastasis
• Represents shearing separation of the pubic
• Normal distance b/t pubic bones should not
exceed 8mm in non-pregnant adults or 10mm
in children
• Often present with unilateral dislocation of SI
• Yochum, T.R. (2005) Yochum and Rowe’s
Essentials of Skeletal Radiology, Third Edition.
Lippincott, Williams and Wilkins: Baltimore.

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