Pelvis and abdomen Flashcards
Pelvis introduction
u The Pelvis is one of the most common examinations performed (Harding et al 2014)
u Various mechanisms/history result in requiring a pelvis examination, including blunt trauma, mechanical falls, degenerative change and pathological concerns
u AP Pelvis is regarded as the standard projection, however there are several supplementary projections including Lateral, Trauma lateral (HBL), Judet, inlet, outlet and frogs lateral
Pelvis: clinical indications
u Trauma – Examples?- fall, road traffic accident
u Follow-up imaging – Examples?- follow up 6-8 weeks to see if bones are still aligned.
u Primary or secondary tumours
u Perthes disease – Why?- Femoral head doesn’t grow properly
u OA
u Congenital abnormalities (eg CDH)
u Slipped epiphysis – Population? Young people
Body positioning for AP Pelvis and abdomen
Supine
Pelvis surface anatomy and palpation points
- Iliac crests
- ASIS- anterior superior iliac spine
- Pubic symphysis
- Greater Trochanters
- Lesser trochanters
- Sacro-illiac joints
- Umbilicus
- Xyphoid sternum
Surface anatomy
iliac crest
sacrum
pubic symphysis
Pelvis: considerations
u Radiation projection – How?- bigger the SA, the more important the collimation is.
u LMP and pregnancy – Range?- ages 12-55 asked when their last period was.
u Planes, surface anatomy/landmarks
u Previous surgery – What considerations? If the patient has had any metal work you must not use the AC
Pelvis patient positioning
- Patient supine on XR table, legs extended
- Medial Sagittal plane in midline and perpendicular to XR table
- ASIS equidistant from table top – Avoids rotation
- Shoulders in same transverse plane
- Separate heels, medially rotate legs 10° - 15° so that toes touch
Pelvis Centering
Central ray vertical to the cassette
In midline of patient 5cm above symphysis pubis
or
In midline of patient between level of ASIS and superior border of symphysis pubis
Common sense approach required when palpating for bony landmarks
pelvis Tips and tricks
- Ensure correct protocol is selected on workstation when using DR as exposures vary
- Centre x-ray tube to Bucky
- Reduce magnification as much as possible
- Look for classic signs of trauma and act accordingly
- Once patient position is established and centred, only move table top
- Ensure iliac crests will be visualised
- Ensure you image doesn’t have ‘blackout’
Male v Female pelvis
female have:
lighter bones
broader and shallower
inlet is larger and oval shaped
wider sacrum with posterior curve
smaller acetabulum
ischial spine projected outward
AP Hip
u Patient supine on XR table, legs extended
u MS plane in midline and perpendicular to XR table
u ASIS equidistant from table top
u Separate heels, internally rotate legs 10° - 15° so that toes touch
u Central ray vertical to the cassette
u Bisect an imaginary line between ASIS and symphysis pubis and move down 2½”
Turned lateral
u Patient supine on XR table, legs extended
u MS plane in midline and perpendicular to XR table
u Turn pt 45° onto affected side - pad behind back
u Align hip to midline of table
u Flex affected hip + knee (lateral thigh 90° to body and in contact with XR table)
u Central ray vertical to the cassette
u Bisect an imaginary line between ASIS and symphysis pubis and move down 2½cm
HBL Lateral hip
- Patient supine on the table
- MSP coincident with the centre of the Bucky
- Unaffected leg is raised so femur is at 90o
- Knee flexed and lower leg supported
- Cassette placed at the side of the affected hip parallel to femoral neck
- Central ray perpendicular to cassette
- Centre to the hip joint, just below crease of groin (Cassette)
Frog lateral
Only used on paediatrics - femoral epiphysis.
Judet views
Less common, 2 oblique x-rays right and left. Superimposes the ilium and superimposes the pubic bones.
