Pelvis Positioning Flashcards
> 90 degree pubic arch
Obtuse angle
Female pelvis
<90 degree pubic arch
Acute angle
Male pelvis
Articulation between the right and left ilia and the sacrum
Sacroiliac (SI) joints
Articulation of the head of the femur with the acetabulum
Hip joint
Junction of the right and left pubic bones in the midline
Pubic symphysis
What part of the femur is common to break due to axial loading?
Neck
In anatomical position, how is the head of the femur positioned?
15-20 degrees anterior
*anatomical position - true AP of knee, leg, ankle but NOT hip
T/F
In anatomical position (feet pointing forward) the lesser trochanters are visible
True
If the hip and leg are in internal rotation, where are the greater and lesser trochanters seen?
Greater - in profile laterally
Lesser - superimposed
If the hip and leg are in external rotation, where are the greater and lesser trochanters seen?
Greater - not in profile
Lesser - in profile medially
What degree of internal rotation of the feet is wanted for AP projections of the pelvis/hip?
15-20 degrees to place hip in true AP
What is asymmetric rotation of the feet an indication of?
Possible hip fracture
What are the most common bony landmarks for palpating?
Iliac crest
ASIS
Where is the neck of the femur located from ASIS?
1-2” medial
3-4” distal
T/F
The highest point of the greater trochanter lies in the same horizontal plane as the midpoint of the hip joint and coccyx
True
What is the standard SID for all pelvis/hip projections?
40” (102cm)
What are the breathing instructions for every pelvis/hip projection?
Suspend respiration
What projections are done for non-trauma pelvis?
Ex. OA
-AP non trauma pelvis
-bilateral frog leg
-unilateral frog leg
What projections are done for non-trauma proximal hip/femur?
Ex. Hip pinning
-AP hip
-AP oblique (Lauenstein)
What projections are done for trauma pelvis?
-trauma pelvis
-inlet/outlet
-judet (looking at acetabulum)
What projections are done for trauma of proximal femur/hip?
-AP hip
-axiolateral
What projections are done for trauma ilium?
-AP and PA
What is the kv range for all projections, except axiolateral?
85 +-5
What AEC cells are used for AP pelvis?
Left and right cells
IR horizontal
-patient supine
-MSP centered to midline
-equal ASIS to table distance on both sides, midway between symph and ASIS
-medially rotate legs and feet 15-20 degrees to place femoral necks parallel with IR
AP pelvis
What AEC cell is used for an AP hip?
Center cell
IR vertical
-patient supine
-no rotation of pelvis
-medially rotate lower limb 15-20 to place femoral neck parallel to IR
-CR perpendicular to femoral neck
-collimate to include ASIS
AP hip
T/F
Unilateral frog leg projections should only be used for non-trauma clinical indications
True
What AEC cell is used for unilateral frog leg hip
Center cell
Vertical IR
What method is contraindicated if fracture is suspected?
Unilateral frog leg
T/F
Grids are used for all pelvis/hip projections
True
-flex leg 60-70 degrees
-abduct thigh 45 degrees
-center ASIS to midline of IR
-CR perpendicular to femoral head or neck
Unilateral frog leg
What AEC cells must be used for bilateral frog leg?
Left and right
IR horizontal
-flex hips/knees 60-70 degrees
-abduct thighs 45 degrees
-place soles of feet together
-CR 3” below level of ASIS
-collimate 5” below symph
AP bilateral frog leg
-method is contraindicated if fracture is suspected
-commonly done for recheck hip pathologies: prosthesis, hip pinning
-prevents foreshortening of distal hip
AP oblique hip (Lauenstein)
What AEC cell is used for AP oblique hip Lauenstein?
Centre cell
Vertical IR
-rotate toward affected side to an oblique position until femur is in contact with the tabletop parallel to IR
-CR perpendicular through hip crease (midway from ASIS and symph)
AP oblique hip Lauenstein
T/F
Feet are NEVER rotated for trauma projections
True
Which projection is the only true lateral, and best for trauma?
Axiolateral
Can assess the ant/post displacement of fractures
Assess medial/lateral displacement of fractures
AP
What kv range and AEC are used for axiolateral hip
90+-5
AEC not used
-flex knee of unaffected limb to place thigh vertical
-IR landscape with upper border in crease above iliac crest
-CR horizontal and perpendicular to long axis of femoral neck
Axiolateral hip
Bilateral view of the bilateral pubis and ischium to allow assessment of pelvic trauma for fractures and displacement
AP axial outlet
-CR angled cephalad 20-35 degrees for males and 30-45 for females
-CR directors to a midline point 1-2” distal to the superior border of the symph or GT
AP axial outlet
What AEC is used for AP axial outlet?
Centre
Horizontal IR
Assessment of pelvic trauma for posterior displacement of inward or outward rotation of the anterior pelvis
AP axial inlet
-angle CR caudad 40 degrees
-CR directed to a midline point at level of ASIS
AP axial inlet
What AEC cells should be used for AP axial inlet?
Left and right
Horizontal IR
What projection is usually done for acetabular fractures to view upside and downside
AP oblique acetabulum (Judet)
What AEC cells should be used for AP oblique acetabulum Judet?
Unilateral - centre
Vertical IR
Bilateral - left and right
Horizontal IR
-Recumbent 45 degree posterior oblique position with affected side down
-CR perpendicular and cnetered to 2” distal and 2” medial to downside ASIS
AP oblique acetabulum Judet
External rotation - affected side down
-Recumbent 45 degree posterior oblique position with affected side up
-CR perpendicular and cnetered to 2” distal and 2” medial to upside ASIS
AP oblique acetabulum Judet
Internal oblique - affected side up
Anterior rim and posterior ilioischial column demonstrated
Judet
Downside (affected side closer)
Posterior rim and anterior iliopubic column demonstrated
Judet
Upside (affected side away)
What projections are required for ilium projections?
AP and lateral
Right side: RPO/RAO
Left side: LPO/LAO
What AEC cell is used for ilium projections?
Centre
Vertical IR
From supine position: elevate the unaffected side approx. 40 degrees to place the broad surface of the wing of the affected ilium PARALLEL with the plane of the IR
-Center IR at level of ASIS
Ilium projection (AP)
RPO/LPO
From a prone position: centre the Sagittal plane passing through the hip joint of the affected side to the midline of the grid
Elevate the unaffected side about 40 degrees to place the affected ilium PERPENDICULAR to the plane of the IR
-centre IR at level of ASIS
Ilium projection (lateral)
RAO/LAO
