1. Fractures and Dislocations of the Pelvis

2. 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#sacralhttp://radiographics.highwire.org/content/21/1/83.full

3. 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

4. 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.accessphysiot herapy.com/searchResults. aspx?searchStr=iliac+wing+ fractures&rootterm=iliac+ wing+fractures&rootID=49 853&searchType=1&searc hSource=1 http://medorder.blogfa.com/post-130.aspx

5. 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

6. 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

7. 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

8. 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

9. http://roentgenrayreader.blogspot.com/2010/07/pelvic-avulsion-fractures.html

10. 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

11. 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

12. References Yochum, T.R. (2005) Yochum and Rowe’s Essentials of Skeletal Radiology, Third Edition. Lippincott, Williams and Wilkins: Baltimore.