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

• 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://www.accessphysiotherapy.com/searchResults.aspx?searchStr=iliac+wing+fractures&rootterm=iliac+wing+fractures&rootID=49853&searchType=1&searchSource=1

http://medorder.blogfa.com/post-130.aspx

Fractures of the IliumAcetabular 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

– AIIS- avulsed by avulsed by rectus femoris muscle

http://bjsm.bmj.com/content/39/3/e16.full#global-tab-decision-support

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 osteo- chondroma

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.