Fractures and Dislocations of the
Pelvis
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
http://www.imageinterpretation.co.uk/pelvis.html#sacral
http://radiographics.highwire.org/content/21/1/83.full
Coccygeal Fractures
• Usually transversely oriented
• Best seen on lateral view
– May show angulation or
anterior displacement of
distal fragment
http://www.physioblasts.org/p/forum/forum_viewtopic.php?6183
Fractures of the Ilium
• Iliac wing fxs.- AKA Duverney fx.; splitting of iliac wing from
direct lateral trauma
http://www.accessphysiot
herapy.com/searchResults.
aspx?searchStr=iliac+wing+
fractures&rootterm=iliac+
wing+fractures&rootID=49
853&searchType=1&searc
hSource=1
• 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
http://medorder.blogfa.com/post-130.aspx
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
http://www.learningradiology.com/
http://radiopaedia.org/cases/acetabular-fracture-1
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
http://bjsm.bmj.com/content/39/3/e16.full#global-tab-decision-support
– AIIS- avulsed by avulsed by rectus
femoris muscle
http://radiopaedia.org/images/358415
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
bilaterally
– Fragments may rupture the bladder
http://www.sciencedirect.com/science/article/pii/S0022534705689185
Pubis and Ischium Fractures
• Avulsion fractures:
– Symphysis pubis- avulsion by major adductor muscles
at superior or inferior pubic rami near pubic
articulation
– Ischial tuberosity (rider’s bone)- avulsion by hamstring
attachment
• Frequently bilateral
• Fragment may show
overgrowth over time and
get mistaken for osteochondroma
http://www.auntminnie.com/index.aspx?sec=ser&sub=def&pag=dis&ItemID=77031
http://roentgenrayreader.blogspot.com/2010/07/pelvic-avulsion-fractures.html
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
occur
http://radiopaedia.org/cases/pelvic-open-book-fracture-1?fullscreen=true
Pubic Diastasis
• Represents shearing separation of the pubic
articulation
• 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
joint
http://www.e-radiography.net/radpath/d/diastasis_symphysis.htm
References
• Yochum, T.R. (2005) Yochum and Rowe’s
Essentials of Skeletal Radiology, Third Edition.
Lippincott, Williams and Wilkins: Baltimore.