Past Positioning Questions Flashcards
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how many bones in adult vertebral column?
26
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most post. part of typical vertebra?
spinous processes
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joints btw articular processes of vertebra
zygapophyseal joints
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Does C1 have a vertebral body?
no
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what must tech make sure to do on spine XRs to improve the vis. of spine?
coll. lat borders
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AP C-Spine CR?
CR 15-20º cephalic to C4
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why is AP C-spine angled 15º cephalic?
to open joint spaces
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During AP “open mouth”, an imaginary line btw what 2 landmarks is made perp to IR?
lower margin of incisors/mastoid tip (skull base)
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AP “Open Mouth” dens shows what?
C1 & C2
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Is the Judd method intended to show the zygapophyseal joints btw C1 & C2?
no
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what pos’s project dens thru shadow of foramen magnum when upper portion of dens is obscured by teeth, when skull base and upper incisors are superimposed?
Fuchs/Judd method
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C-vert. contain what in their transverse processes?
foramen
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detail is improved on a lat c-spine by using what?
sm focal spot
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What XR shows articular pillars & zygapophyseal joints on C-spine?
lat C-spine
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what is done on an ant. obl c-spine to prevent the superimposition of the mandible?
extend chin
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an ant obl c-spine shows the IV foramina/pedicles ______ to IR
closest
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an LAO c-spine show’s what?
L IV foramina/pedicles
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which obl’s are preferred for C-spine? why?
ant. obl.; less thyroid dose
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CR for post obl c-spine?
15º cephalic to C4
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An RPO of c-spine shows what?
L IV foramina/pedicles
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In a post obl c-spine, the IV foramina/pedicles _______ to IR are shown
furthest
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CR AP T-spine?
perp T7 (3-4” inf. jugular notch)
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what manual technique is done in the lat T-spine to enhance the visualization of the vertebral bodies?
low mA & 3-4s exposure T (w orthostatic breathing)
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the Lat T-spine shows what?
open IV foramina
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on the lat T-spine, the vertebral column must be _______ to tabletop to open up IV joint spaces
II
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what can be done on a lat T-spine to improve vis. of post. spine by preventing excessive density along post. aspect of spine?
pb apron behind pt
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which XR best demonstrates a compression fracture of T-spine?
lat T-spine
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which XR best demonstrates C7-T1?
Swimmer’s lat/Twining method
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what is performed when the upper aspect of T-spine is obscured by shoulders, when the upper T-spine is the area of interest?
Swimmer’s lat/Twining method
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if pt enters ER bc of MVA & is on backboard w C-collar, and initial XR only shows C1-C6, & no CT is available, what XR should be performed?
horizontal beam Swimmer’s lat
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what kind of contrast/latitude is preferred for L-spine?
short-scale, narrow latitude
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iliac crest is located at the level of?
L4-5
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what 2 L-spine XRs would show a possible compression fracture of L3, by best demonstrating body of L3 & IV joint spaces above and below it?
collimated AP & lat L-spine
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if you must perform an L-spine on a pregnant female, what 3 things should a tech do?
- use higher kVp & lower mAs, 2. increase SID,3. coll. as much as possible
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neck of Scottie dog?
pars interarticularis
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what is the sm bone found btw the sup. & inf. articular processes?
pars interarticularis
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ear of scottie dog?
sup. articular process
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eye of scottie dog?
pedicle
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foot of scottie dog?
inf. articular process
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nose of scottie dog?
transverse process
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scottie dogs are only seen on what projections?
obl L-spine XRs
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what XRs best show the degree of movement at the fusion site (after a spinal fusion was performed at L3-4)?
lat hyperextension & hyperflexion
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why should a pt flex knees during an AP L-spine?
to reduce lordotic curve/straighten spine
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CR for AP L-spine?
perp to iliac crest
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what should tech do to prevent scatter from reaching IR on a lat L-spine?
pb mat behind pt
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what is shown on a lat L-spine?
IV foramina, IV joint/disk spaces of L-spine
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how much is a pt rotated for an obl L-spine?
45º
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what pos should you place a pt to see the L apophyseal joints of L-spine?
LPO
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how much rotation should you rotate pt to see the zygapophyseal joints at L1-2?
50º obl
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how much rotation should you rotate pt to see the zygapophyseal joints at L5-S1?
30º obl
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what pos demonstrates the R apophyseal joints of L-spine?
RPO
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how much body rotation is needed to best demonstrate the L3-4 zygapophyseal joints?
45º
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which ant obl L-spine XR will show the R apophyseal joints?
LAO
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CR for lat L5-S1 spot when pt has insufficient waist support?
5-8º caudad to 1.5” inf. iliac crest & 2” post. ASIS
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for a cone down view of L5-S1 in an AP projection, must angle CR?
30-35º cephalic
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S1-2 is located at the level of?
ASIS
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another term for sacral horn
cornu of sacrum
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term for sup. aspect of coccyx?
base
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an avg of ___ segments make up the adult coccyx
4
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CR for AP Axial Sacrum?
15º cephalic to midway btw pubic symphysis & ASIS
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CR for AP Axial Coccyx?
10º caudad to 2” sup. to pubic symphysis
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CR for lat Sacrum/Coccyx?
perp to 3-4” post. ASIS
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how many degrees do you int. rotate feet for AP pelvis?
15-20º (IF NO FRACTURE SUSPECTED)
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how much do you abduct femora from vertical on a bilat frog/modified cleaves for pelvis?
40-45º
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for the Lauenstein-Hickey method (for unilat hip) the pt is what?
rotated onto affected side until femur touches table and is II to IR
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Lauenstein-Hickey method for hip shows what?
foreshortened femoral neck, but shows head & acetabulum
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humeral epicondyles are _________ to IR for AP Int Shoulder
perp
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humeral epicondyles are __________ to IR for AP Ext Shoulder
II
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AP Int Shoulder shows what?
lesser tubercle in full profile (med)
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AP Ext Shoulder shows what?
greater tubercle in profile (lat)
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CR for AP Int/Ext Shoulder
perp 1” inf. coracoid process (which is 3/4” inf. to lat. portion of clavicle)
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Post Obl shoulder aka?
Grashey method
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Grashey method shows
glenoid cavity in profile; open scapulohumeral joint space
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on Grashey for shoulder, a person w a round/curved back needs ______ rotation to place body of scapula II to IR
more
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how much body rotation is needed for Grashey method?
35-45º towards affected side
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breathing technique for clavicle?
full inspiration (to raise clavicles out of lung field)
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CR for AP Axial clavicle?
15-30º cephalic to midclavicle
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thin pt’s need ___________ angle than thick pt’s for AP Axial clavicle
10-15º more
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what must pt do for positioning of AP scapula?
abduct arm 90º and supinate hand (salute)
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which landmarks are used for positioning go scapula “Y” lat?
sup. angle of scapula & AC joint (rotate until imaginary line btw is perp to IR)
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min weights used for AP AC joints w weights?
5-8 lbs
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what is done to project the AC joint sup. to acromion for optimal vis.?
Alexander method, CR 15º cephalic to midpoint btw AC joints
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What SID for AC joints?
72”
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breathing technique for AP scapula?
orthostatic breathing
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3 potential errors in skull positioning
- excessive neck flexion/extension2. head rotation/tilt3. incorrect CR angle
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how do you find the sella turcica?
3/4” ant. & 3/4” sup. to EAM
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sella turcica houses the?
pituitary gland
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neuro XRs use _____ focal spot
sm
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which XR puts the petrous ridges below the maxillary sinuses?
Parietoacanthial (Waters) method
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what must be done before performing SMV XRs?
rule out fractures/subluxation of C-spine
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pt enters ER w possible fracture of R zygomatic arch, what is the best XR routine?
SMV, bilat obl tangential, & AP Axial
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what line is II to IR for SMV of zygomatic arches?
IOML
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if pt cannot hyperextend neck enough for SMV, what should tech do?
make CR perp to IOML
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what is the pt pos for obl inferosuperior tangential zygomatic arch (Mays view)
(from SMV pos) pt must rotate & tilt 15º toward affected side
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CR for AP axial Towne zygomatic arch when IOML perp to IR
37º caudad to 1” sup. glabella (exiting level of gonion)