knee, patella, femur Flashcards
kVp range for AP, oblique, and lateral knee
65-80 kVp
to position the knee for an AP knee, do the following:
______________________________________
rotate leg internally 3-5 degrees for a true AP or until inter-epicondylar line is parallel to plane of IR
to position the knee for an oblique (medial/internal) knee, do the following:
______________________________________
internally rotate entire leg 45 degrees
to position the knee for an oblique (lateral/external) knee, do the following:
______________________________________
externally rotate entire leg 45 degrees
for an AP knee, rotate leg _________________ for a true AP or until inter-epicondylar line is (parallel/not parallel) to plane of IR
internally 3-5 degrees, parallel
for an AP knee, align CR ________________________________; direct CR to a point ______ distal to the ____ of the patella
parallel to articular facets (tibial plateau); 1/2 inch; apex
CR angulation for an AP and oblique(s) knee exam…
thinner patient =
average patient =
thicker patient =
thinner patient = 5 caudad
average patient = 0
thicker patient = 5 cephalad
What is a “thinner”/”average”/”thicker” patient measurements when measuring for AP and oblique knee exams?
less than 19 cm = thinner
19-24 cm = average
greater than 24 = thicker
in an AP knee, the ______________ joint space should be (open/closed)
femorotibial; open
in an AP knee, the femorotibial joint space should be open with the articular facets of the tibia seen on end with only _____________________________
minimal surface area visualized
in an AP knee, the medial half of the fibular (head/base) (should/should not) be superimposed by the tibia
head; should
for an oblique (medial/internal) knee, direct the CR ___________
1/2 inch distal to apex of patella
for an oblique (lateral/external) knee, direct the CR ___________
1/2 inch distal to apex of patella
in an oblique (medial) knee, the patella superimposes __________
the medial femoral condyle
in an oblique (medial) knee, the __________________ are well demonstrated and the _________________ appear unequal
lateral condyles of the femur and tibia; medial and lateral knee joint spaces
in an oblique (medial) knee, the fibula is shown (with/without) superimposition. Approximately ____ of the patella should be seen free of superimposition by the femur
without; half
in an oblique (medial) knee, the tibiofibular articular is (open/closed)
open
in an oblique (lateral) knee, direct the CR ________
1/2 inch distal to apex of patella
in an oblique (lateral) knee, the patella superimposes the _____________
lateral femoral condyle
in an oblique (lateral) knee, the _____________ and ____ are seen in profile
medial condyles of femur, tibia
in an oblique (lateral) knee, the proximal fibula (is /is not) superimposed by the proximal tibia
is
in an oblique (lateral) knee, approximately ____ of the patella should be seen free of superimposition by the femur
half
a lateral knee utilizes the _________ projection
mediolateral
for a lateral knee in the lateral recumbent position, the knee is to be flexed ____ degrees with the affected side ____
20-30 degrees; down
what is an alternative for a lateral knee if patient is unable to flex the knee?
horizontal beam
a true lateral knee has the femoral epicondyles ____________ and plane of patella is ________
directly superimposed; perpendicular to the plane of the IR
the CR angulation on a lateral recumbent knee should be __________
5-7 degrees cephalad
Direct CR to ________________ for lateral knee (both lateral recumbent and horizontal beam)
1 inch distal to medial epicondyle
in a lateral knee, the _____________ should be open
patellofemoral and knee joints
over rotation in a lateral knee will show ________________
less superimposition of fibular head
under rotation in a lateral knee will show ________________
more superimposition of fibular head
a true lateral knee without rotation shows ____________________ of the femoral condyles ___________
posterior borders, directly superimposed
in a lateral knee, the 5-7 degree angulation of the CR causes:
direct superimposition of distal borders of the condyles
for an AP femur (proximal and distal), CR is directed _________
midpoint of femur/IR
for an AP femur, the lower IR margin should be approximately _________ below knee joint
2 inches
in an AP femur, the knee joint (will/will not) appear open. The patella will be ____________
will not; slightly medial
kVp range for AP and lateral femur
75-85 kVp
a lateral recumbent femur (should/should not) be attempted in a trauma
should not
knee flexion for lateral recumbent femur
45 degrees
for a lateral femur, CR is directed _________
perpendicular to femur and directed to midpoint of IR
a true lateral femur will have ___________ and _______________
anterior and posterior margins of medial and lateral femoral condyles superimposed; open patellofemoral joint space
a lateral recumbent femur will have a ________ projection
mediolateral
the upper IR margin on a lateral femur should be at the _____
ASIS
AP weight-bearing knees will have the CR at this angle
perpendicular to the IR
where is the CR directed with an AP weight bearing knee?
between the knees, 1/2 inch distal to patella apex
in an AP knee, the patella is just __________ to the femoral patellar surface and _____________ to midline of the knee
proximal, slightly lateral
what is the SID for Merchant Board sunrise patella?
48 or 72 inch SID
kVp range for Camp Conventry method
70-80 kVp
Camp Conventry: patient is _____. Flex knee _________.
CR: caudad angle ________________
prone, 40-50 degrees, to match the flexion of the knee
for Camp Coventry, the CR is directed at __________
popliteal crease
CR angle for PA patella
perpendicular to IR
CR angle for lateral patella
perpendicular to IR
where is the CR directed entered at for a lateral patella?
mid-patellofemoral joint
where is the CR directed entered at for a PA patella?
mid-popliteal/midpatella area
for a true PA patella, the inter-epicondylar line is __________ to the IR; how is this achieved?
parallel; rotating knee 5 degrees internally (similar to an AP knee)
how many inches of overlap is necessary for femur exams?
at least 2 inches
AP proximal femur positioning
-Make sure pelvis (is/is not) rotated (_____________)
-Rotate leg __________ to place the femoral neck _______to IR for a true AP of the proximal femur
-Place top of cassette to the level of _________
-is not (ASISs equidistant from table)
-15-20° internally, parallel
-Place top of cassette to the level of the ASIS
in an AP proximal femur, the obturator foramen should be ____
open
AP distal/mid femur positioning
-Rotate affected leg _____________ so that the ___________________
medially 5º; epicondyles are parallel with the IR
the AP femur will show the _________
the lateral femur will show the ___________
AP = greater trochanter
lateral = lesser trochanter
kVp range for Beclere method
65-80 kVp
Positioning for Beclere method: Flex knee __________ (place support under IR as needed to place it firmly against the posterior thigh and lower leg)
45-50º
CR angle for Beclere method
approx. 40-45 cephalad, directed perpendicular to lower leg
CR centering for Beclere method
1/2 inch distal to apex of patella
Positioning for a lateral patella
___________ projection
femoral epicondyles _________________; plane of patella _____________to plane of IR
flexed knee at ____________
mediolateral
directly superimposed; perpendicular
flexed knee at 5-10 degrees
What are the 2 intercondylar fossa views we covered in lecture?
Camp Coventry, Beclere
PA weight-bearing knees will have the CR at this angle
10 degrees caudad (PA only; AP is perpendicular)
Hughston is method for what type of exam?
patella tangential/sunrise
Camp Conventry is method for what type of exam?
intercondylar fossa
Merchant board is method for what type of exam?
patella tangential/sunrise
Settegast is method for what type of exam?
patella tangential/sunrise
Positioning for Hughston exam
patient prone, knee flexed 50-60 degrees from full extension
CR angle for Hughston method
45 degrees cephalad
CR entrance for Hughston method
tangential to patellofemoral joint
Positioning for Settegast exam
patient either prone or sitting
-knee at least 90 degree flexion for prone
-knee “90 degree flexion” for seated (less in real life)
CR angle for Settegast method (specifically for the prone position)
15-20 degrees tangential to patellofemoral joint space
CR angle for Settegast method (as learned at clinical for seated position)
15-20 degrees tangential to patellofemoral joint space
**not in textbook, but from clinical & for memory’s sake = crosshairs of light beam at patellofemoral joint space (107 degrees cephalic)
Positioning for merchant board exam
Place patient in supine position on the table with legs hanging off of the end and knees flexed 40º resting on the Merchant Board
distal femurs resting on tabletop; knees and feet together
CR entrance for Merchant board exam
midway between patellae (bilateral)
CR angle for Merchant board exam
caudad, 30 degrees from horizontal plane (CR 30 deg. from femur)
What muscle must be relaxed for a Merchant Board exam? Why?
Quadriceps femora muscles, to prevent subluxation of the patellae.
Can be pulled into the intercondylar sulcus/groove —> false reading
Camp Coventry positioning
Patient prone, knee flexed 40-50 degrees
CR angle for Camp Coventry
40-50 degrees caudad (perpendicular to lower leg)
CR entrance for Camp Conventry
Center to knee joint emerging at distal margin of patella
Positioning for Holmbald method
Patient on all fours or partially standing; kneeling on board, weight on opposite leg
Lean patient forward 20-30 degrees
CR angle for Holmbald method
Perpendicular
CR entrance for Holmbald method
Midpopliteal crease
Positioning for Hobbs method
Patient sitting on chair/table with board under knees; feet slightly underneath chair/table
CR angle for Hobbs method
Perpendicular to IR
CR entrance for Hobbs method
Mid patellofemoral joint
SID considerations for Hobbs and Merchant exam
Increase to reduce magnification
