-AP, Oblique, Lateral
-Table Top, 40-48 side, 10×12,
-Dorsiflex on Oblique and Lateral
Basic Foot Projection
-AP, Oblique, Lateral
-Table Top, 40-48 side, 8×10 or 10×12,
Basic Toe Projection
Lateral and Axial
Name 2 projections for the Calcaneus?
Ap, oblique, mortise and medial lateral.
-8×10, 40 sid, table top
Name basic projections for ankle?
The inferior tibiofibular and the talofibular articulation will not be “open” nor shown in profile.
On a true AP projection of the ankel what will not be open nor shown in profile?
Must include the tubersoity of the 5th metatarsal which is most commonly fracture. (JONES FRACTURE)
On the mediolateral of the ankle what must be included.
distal ends of tibia and fibula and tibiofibular articulation is demonstrated.
What is shown on the AP Oblique medial rotation?
AP & Lateral, 14×17 48 sid, include both joints 1 1/2-2 inches beyond, also dorsi flex on the Ap
What are the basic projections of the lower leg?
AP, Lateral, Oblique, check hospital for views, 10×12, 40 sid, CASSETTE IN BUCKY! Knee will probably be more than 10 inches.
What are the basic projections of the knee?
ASIS 18 and below: 5 caudad
25 and up: 5 cephalad
What do you measure for an AP and Oblique knee projection?
On which knee view will there be a 5 degree cephalic anglulation of the CR?
The base of the fifth metatarsal is a common fracture site
Plantar surface near head of first metatarsal
Where are the sesamoid bones of the foot most commonly located?
What is the name of the tarsal bone found on the medaial side of the foot between the talus and three cuneiforms?
Which tarsal bone is considered to be the smallest?
What is another term for the talocalcaneal joint?
The distal tibial joint surface is called the:
Affected MTP joint
What is the correct central ray centering placement for an AP projection of the toes?
10 to 15 degree
Which type of central ray angle is required for an AP projection of the toes?
30 to 40 degree
How much foot rotation is required for the AP oblique, medial rotation projection of the foot?
What is another term for the AP projection of the foot?
10 degree posterior
What CR angle is generally required for the AP projection of the foot?
AP oblique-medial rotation
Which projection of the foot best demonstrate the cuboid?
What is the name of the deep depression found on the posterior aspect of the distal femur?
5 to 7 degree
A line drawn across the most distal aspect of the medial and lateral femoral condyles would be ___________ from being at a right angle (90degree) to the long axis of the femur.
Which pathologic condition involves a ligment found in the foot?
Which conditions may produce the radiographic appearance of a destructive lesion with irregular periosteal reaction?
What is the common term for chondromalacia patellae?
Base of the 3rd metatarsal
Where is the central ray placed for a plantodorsal axial projection of the calcaneus?
AP oblique (15 to 20degree medial rotation)
Which ankle projection is best for demonstrating the mortise of the ankle?
Which imaginary plane should be placed parallel to the IR for an AP projection of the knee?
Which joint space should be open or almost open for a well-positioned AP oblique knee projection with medal rotation?
A 5 to 7 degree cepalad angle of the central ray for a lateral projection of the knee helps superimpose the distal borders of the medial and lateral condyles of the femur.
The cuboid articulates with the four bones of the foot.
The calcaneus articulates with the talus and the
Which three bones make up the ankle joint?
The three bones of the ankle form a deep socket into which the talus fits. The socket is called the
The distal tibial joint surface forming the roof of the distal ankle joint is called the
The ankle joint is classified as a synovial joint with _______ type movement
The ______ is the weight-bearing bone of the lower leg.
What is the name of the large prominence located on the midanterior surface of the proximal tibia that serves as a distal attachment for the patellar tendon?
What is the name of the small prominence located on the posterolateral aspect of the medial condyle of the femur that is an identifying landmark to determine possible rotation of a lateral knee?
A small, triangular depression located on the tibia that helps form the distal tibiofibular joint is called the
The articular facets of the proximal tibia are also referred to as the
10 to 15 degree
The articular facets slope ________ degree posteriorly
APEX or Styloid Process
The most proximal aspect of the fibula is the
The exteme distal end of the fibula form the
What is the name of the largest sesamoid bone in the body
What are two other names for the patellar surface of the femur?
Intercondylar Fossa or Notch
What is the name of the depression located on the posterior aspect of the distal femur?
The slightly raised area located on the posterolateral aspect of the medial femoral condyle is called the
What are the two palpable bony landmarks found of the distal femur?
The correct terms for the joint between the patella and distal femur
The correct terms for the joint between the two condyles of the femur and tibia
What is another term for osteomalacia?
The formal name for “runner’s knee” is
To opens up the IP joints and MTP joints
Why is the central ray angled 10 to 15 degree toward the calcaneus for an AP projection of the toes?
Base of 3rd metatarsal
Where is the central ray centered for an AP oblique projection of the foot?
Which projection is best for demonstrating the sesamoid bones of the foot?
15 to 20 degree
The foot should be dorsiflexed so that the plantar surface of the foot is _______ degree from vertical for the sesamoid projection
To open up IP joints and MTP joints
Why should the central ray be perpendicular to the metatarsals for an AP projection of the foot?
NONE; use perpendicular central ray
If a foreign body is lodged in the plantar surface of the foot, which type of central ray angle should be used for the AP projection?
Second to Fifth
Rotation can be determined on a radiograph of an AP foot projection by the near-equal distance between the _______ metatarsals
Which oblique projection of the foot best demonstrates the navicular and the first and second cuneiforms with minimal superimposition?
Which oblique projection of the foot best demonstrates the majority of the tarsal bones?
Which projection tends to place the foot into a truer lateral position:
AP & Lateral Weight-bearing projection
Which type of study should be performed to best evaluate the condition of the longitudinal arches of the foot?
40 degree cephalad
How shold the central ray be angled from the long axis of the foot for the plantodorsal axial projection of the calcaneus?
1 inch inferior to medial malleolus
Where is the central ray placed for a lateral projection of the calcaneus?
Lateral surface of joint
Which joint surface of the ankle is NOT typically visualized with a correctly positioned AP projection of the ankle?
To demonstrate a posible fracture of the 5th metatarsal tuberosity.
Why should AP, 45degree oblique, and lateral ankle radiographs include the proximal metatarsals?
15 to 20 degree (medially)
How much (if any) should the foot and ankle be rotated for an AP mortise projection of the ankle?
45 degree AP oblique with medial rotation
Which projection of the ankle best demonstrates a possible fracture of the lateral malleolus?
Projected over the posterior aspect of the distal tibia
With a true lateral projection of the ankle, the lateral malleolus is:
To include both joints for a lateral projection of the tibia and fibula for and adult, the technologist may place the cassette ________ in relation to the part.
3 to 5 degree cephalad
What is the recommednded central ray angulation for an AP projection of the knee for a patient with thick thighs and buttock. (greater than 24cm)
1/2 inch (1.25cm) distal to apex of patella
Where is the central centered for an AP projection of the knee?
AP oblique, 45degree medial rotation
which basic projection of a knee best demonstrated the proximal fibula free of superimposition?
For the AP oblique projection of the knee, the __________ rotation best visualized the lateral condyle of the tibia and the head and neck of fibula.
5 degree cephalad
What is the recommended central ray placement for a lateral knee position on a tall, slender male patient with a narrow pelvis?
20 to 30 degree
How much flexion is recommended for a lateral projection of the knee?
Inproper angle of the central ray
Which positioning error is present if the distal borders of the femoral condyles are not superimposed on a radiograph of a lateral knee?
Which positioning error is present if the posterior portions of the femoral condyles are not superimposed on a lateral knee radiograph?
AP or PA weight-bearing knee
Which special projection of the knee best evaluates the knee joint for cartilage degeneration or deformities?
Medial or Collateral Ligament damage
AP knee stress projections are performed to demonstrate:
40 degree flexion
How much flexion of the lower leg is required for the Camp-Coventry projection when the central ray is angle 40 degree caudad?
10 degree caudad
What tye of CR angulation is required for the PA axial weight-bearing projectin (Rosenberg method)?
Intercondylar Fossa And the patella
The Merchant Method & the Tangential (Axial or Sunrise/Skyline) Projections demonstrate these two structures
20 to 30
The amount the knee is flexed in the lateral position
The PA Axial (Camp- Coventry Method) is used to demonstrate this structure
The CR angle for an axial calcaneous projection
The upper, or superior, portion of the patella
The deep depression found on the posterior aspect of the distal femur
The CR angle & direction that are generally required for the AP projection of the foot
Another name for the AP projection of the foot
Head of the affected metatarsal
The CR centering point for an AP projection of the toes
TRUE or FALSE: A correctly positioned lateral ankle will demonstrate the lateral malleolus superimposed over the posterior half of the tibia
TRUE or FALSE: A 3 to 5 CR angle should be used for an AP knee for patients with thick thighs
AP and Lateral Knee
The Positions that best demonstrate signs of Osgood-Schlatter diseases
AP and Horizontal beam lateral, no flexion
Situation: A patients enters the ER with a transverse fracture of the patella. Which rountines would safely provided the best images of the knee?
TRUE or FALSE: Digital Imaging requires that images be chemically processed
TRUE or FALSE: Digital Images are a numeric representation of the x-ray intensities that are transmitted through the patient
The deep depression found on the posterior aspect of the distal femur
Weight bearing knee study
Situation: A patient is referred to radiology for a possbile Lisfranc Injury. Which of the following positioning routines would best demonstrate this condition?
MTP joint – 10-15° toward calcaneus
Where is CR centered/angle for AP toes
at the MTP joint (for toes) – with leg and foot medially rotated 30-45°
Where is CR centered for AP oblique toes
IP (if #1) or PIP joint (2-5)
Where is the CR centered for Lateral projection of toes
1st MTP joint – when foot is dorsiflexed 15-20° from vertical
Where is CR centered for sesamoid tangential projection
shafts of phalanges and distal metatarsals appearl equally concave on both sides. If one side is concave, that side has been rolled away from the IR
How is no rotation noted for an AP of the toes
digits of interest and a minimum of the distal half of metatarsals
what structures are shown for toe projections
Increased concavity on one side of the phalange shaft and by overlapping soft tissues of digits. Heads of metatarsals should appear side by side w/o overlapping. IP and MTP joints appear open.
How is obliquity evident on an oblique (medial) rotation for toes
increased concavity on anterior surface of distal phalanx and posterior surface of proximal phalanx. The opposing surface of each phalanx will appear straighter.The IP joints should appear open and the MTP joint should be visualized even if superimposed.
How does a true lateral of the toes appear
Profile image of the sesamoid bones at the first MTP joint and borders of posterior margins of 1st to 3rd distal metatarsals in profile – include a minimum of 3. Sesamoids free of superimposition and open space b/w sesamoids and first metatatarsal.
What structures are shown on a sesamoid tangential projection
Pt supine with patient holding toes back with gauze/tape.
What is alternate to the prone position for the sesamoid tangential projection
Disadvantage to the supine position for the sesamoid tangential projection
Base of third metatarsal, 10° toward heel (cephalad). A higher arch requires a 15° angle, and lower arch – 5°
Where is CR centered/angle for AP foot (dorsoplantar)
Base of third metatarsal. Rotate foot 30-40°. CR is perpendicular
Where is CR centered for AP oblique of foot
medial cuneiform / based of 3rd metatarsal – CR is perpendicular
Where is CR centered for Lateral of foot
base of 3rd metatarsal – Angle CR 15° posteriorly to midpoint between feet
Where is CR centered for AP weight-bearing foot
base of 3rd metatarsal – CR horizontal to feet
Where is CR centered for lateral weight bearing foot
AP and Lateral weight-bearing foot projections
What projection of the foot shows the arches
AP and Lateral weight-bearing foot projections may show structural ligaments
What projection of the foot shows the ligaments of the foot (Lisfranc jt)
How much of an angle during an AP projection would be needed for a high arch (foot)
What CR angle is desired when performing a radiograph of a foreign object
40-45° rotation medially
What rotation of the foot best demos the tarsals and proximal metatarsals relatively free of superimposition
Optional lateral oblique
What is an option to the medial rotation of the root
spaces between first and 2nd metatarsals and 1st and 2nd cuneiforms. Also navicular will be well visualized
What does the optional lateral oblique rotation of the foot show
What is the foot rotation for a lateral oblique foot
There is equal distance between the 2nd thru 5th metatarsals. Base of 1st and 2nd metatarsals are separated but the bases of 2-5 are overlaping. The intertarsal joint space between 1st and 2nd cuneiforms is open. Sesamoid bones should be seen thru the head of the 1st metatarsal. MTP joints are open.
How is no rotation evident on an AP foot projection
the 3rd-5th metatarsals are free of superimposition. 1st and 2nd metatarsals should be free of superimposition except for the base areas. The tuberosity of 5th metatarsal is in profile. The jt space around the cuboid and sinus tarsi are open.
How is obliquity evident on an AP oblique foot
Entire foot with 1″ of distal tibia/fibula. metatarsals will be nearly superimposed with only the tuberosity of the 5th metatarsal seen in profile.
The tibiotalar jt is open, the distal fibula is superimposed by posterior tibia and distal metatarsals are superimposed.
If a foot is in a true lateral, what is shown
Open tarsometatarsal jt space and visualization of the jt between the 1st and 2nd cuneiforms
If proper angulation is used on an AP weight-bearing foot, what is seen
base of 3rd metatarsal – 40° from long axis of foot (emerges just distal to lateral malleolus)
Where is the CR centered/angled for the plantodorsal (axial) calcaneus projection
1″ inferior to the medial malleolus
Where is the CR centered for the lateral (mediolateral) calcaneus projection
Calcaneus in profile, navicular and open jt space of calcaneus and cuboid distally. lateral malleolus seen through the talus. Include the ankle joint proximally and talonavicular jt and base of fifth metatarsal anteriorly.
What does the lateral calcaneus projection show
the sustentaculum tali in profile (medially). Entire calcaneus s/b visualized from the tuberosity posteriorly to the talocalcaneal jt anteriorly. Also, an open talocalcaneal jt. space faintly.
What structures are shown on a plantodorsal calcaneus projection
open talcalcaneal jt, tarsal sinus and calcaneocuboid jt space is open.
How is no rotation evident on an a lateral calcaneus
midway between the malleoli – CR perpendicular
Where is the CR centered for an AP ankle
Entire leg is rotated 15-20° medially, and CR is perpendicular to midway between the malleoli
Where is the CR centered for an AP Mortise ankle
Leg is rotated 45°
Foot is dorsiflexed 80-85°
CR is centered to midway between malleoli – perpendicular
Where is the CR centered for an AP oblique ankle
CR is centered directly at medial malleolus – perpendicular
Where is the CR centered for an lateral ankle
CR is centered between the malleoli – perpendicular
Where is the CR centered for an AP stress (inversion, eversion) ankle
Distal one-third of the tib/fib, lateral and medial malleoli, talue and proximal half of the metatarsals. Lateral malleolus will be 15° posterior to the medial malleolus
Mortise will not be open on the lateral portion.
Some superimposition of the distal fib by the distal tibia and talus
What will be visualized on an AP ankle
A ruptured ligament – spreads the ankle mortise
If the mortise is open on an AP ankle, what may be the cause
Distal one-third of tib/fib, tibial plafond, lateral and medial malleoli, talus and proximal 1/2 of the metatarsals. The mortise open on all sides and the proximal 5th metatarsal with malleoli in profile. Only minimal superimposition at the distal tib/fit joint. Normal 3-4 mm mortise space is normal, but an extra 2 mm is abnormal.
What does the 15-20 AP mortise view visualize
the AP medial oblique – 45°
What is the best demonstration of an open fibular (lateral malleolus)
Distal 1/3 of the tib/fib, with distal fibula superimposed by the distal tibia; the talus; calcaneus in profile. The tuberosity of the 5th metatarsal, the cuboid, navicular and base of the 5th metatarsal will be visualized.
What does the lateral ankle view visualize
distal fibula is superimposed over the posterior half of the tibia.
Tibiotalar joint will be open with uniform joint space.
How is no rotation evident on a lateral ankle
What can be used is an AP stress inversion is too painful for the pt
the ankle joint for evaluation of joint separation and ligament tear or rupture. The ankle and leg remain in a true AP position, where the plantar surface is turned medially or laterally.
What do the AP stress ankle projections visualize
What should a tech wear when helping with an AP stress ankle projection
Midpoint of leg – perpendicular
Where is the CR centered for the AP and lateral tib/fib projections
turn the cassette diagonally
What may the tech need to do to get the entire tib/fib on the IR
Increase the SID to 44-48
What can be done to reduce divergence or get more of the body part during a tib/fib projection
Entire tib and fib with both the ankle and knee joints (except in follow-up exams)
What is visualized during an AP leg
Femoral and tibial condyles in profile with intercondylar eminence centered within the intercondylar fossa. Some overlap of the fibula and tibia at both proximal and distal ends
How is no rotation evident on an AP leg
tib and fib in profile with both joints on either end. Overlap at proximal and distal ends. Posterior borders of femoral condyles appear superimposed.
How is proper rotation evident on a lateral leg
Rotate leg 3-5° until intercondylar plane is parallel to IR
CR .5″ distal to apex of patella (parallel to articular facets [tibial plateau] – perpendicular on average, 3-5° caudad on thin, and 3-5° cephalic on thicker pt.
Where is the CR centered for the AP knee
Distal femur and proximal tibia and fibula. femortibial jt space open with articular facets of tibia seen on end. Medial half of fibular head s/b superimposed by tibia. Patella can be visualized through the distal femur.
What is visualized on the AP knee
45 medial rotation (interepicondylar line should be 45° to the IR)
CR .5″ distal to apex of patella
Where is the CR centered for the AP oblique medial knee
distal femur and proximal tib/fib with patella superimposing the medial femor condyle. Lateral condyles of femur and tibia are well demo’d. Medial and lateral knee jt spaces appear unequal.
What is visualized on the AP oblique medial knee
tib/fib articulation is open. Lateral condyles of femur and tibia seen in profile. Head and neck of fibular are not superimposed. 1/2 of patella is seen free of superimposition.
How is obliquity evident on the AP oblique medial knee
45 lateral rotation (interepicondylar line should be 45° to the IR)
CR .5″ distal to apex of patella
Where is the CR centered for the AP lateral oblique knee
0° if average
3-5° caudad for thin pts
3-5° cephalic for thick pts
For knee projections, what is the CR angulation rule
distal femur, proximal tib/fib, with patella superimposing lateral femoral condyle
What is visualized on the AP lateral oblique knee
proximal fibular is superimposed by proximal tibia. Medial condyles of femur and tibia are seen in profile. 1/2 of patella seen free of superimposition by femur. Head & neck of fibula can be seen THRU the tibia (superimposed)
How is obliquity evident on the AP oblique lateral knee
horizontal beam if trauma – lateromedial
at 1″ distal to medial epicondyle
CR 5-7° cephalad for lateral recumbent, knee flexed 20-30°, or 7-10° on short pt with wide pelvis, 5° on tall, male
Where is the CR centered for the lateral knee
Lateral knee projection
What projection should be used to demonstrate Osgood Schlatter disease
the adductor tubercle on the posterior side of the medial condyle. If you see it, there is rotation from a lateral position
Overrotation or underrotation can be determined by identifying which structure
the patella will be drawn into the intercondylar sulcus and may obscure soft tissue detail and mayy result in fragment separation of patellar fractures
Make sure not to flex more than 20-30° (knee) because
distal femur, proximal tibia and fibular, patella in lateral profile. Femorpatella and knee jts should be open
What is visualized on the lateral knee
less superimposition of the fibular head by the tibia
Overrotation on a lateral knee is evident by
more superimposition of the fibular head by the tibia
Underrotation on a lateral knee is evident by
hip width – ranges from 5-10° (5° for thin tall male, 5-7° on average, 7-10° for short pt with wide pelvis)
What does the lateral knee CR angle depend on
posterior borders of the remoral condyles are directly superimposed. The patella is seen in profile with femoropatellar and knee joints space open
How is a true lateral evident on a lateral knee
At what age are weight-bearing knee projections more common
midpoint between knee joints at the level of .5″ below the apex of the patellae – CR is angled 5-10° caudad for a thin pt. – parallel to the tibial plateau for best visualization of open knee jt. spaces.
Where is the CR centered for the weight-bearing bilateral knee – AP
The PA weight-bearing knee
What is the optional projection for the weight-bearing knee
midpoint between knee joints at the level of .5″ below the apex of the patellae – CR is angled cephalic 10° on a thin patient.
Where is the CR centered for the PA weight-bearing knee
20°, thighs against the IR. (CR is pointed 10° cephalad)
What is the flexion for a PA weight-bearing knee
for patients who cannot fully straighten their knee joints, such as arthritic conditions or neuromuscular disorders of the lower limb
When is a PA weight-bearing projection indicated
For cartilage degeneration, radial or lateral collateral ligaments
In general, when is a weight-bearing projection indicated
distal femur, proximal tibia and fibula and femorotibial joint spaces – bilaterally.
What is demonstrated on a weight-bearing projection
symmetric appearance of femoral and tibial condyles. 1/2 of the proximal fibula will be superimposed by the tibia. Knee joints should appear open if CR angle is correct. (Parallel to tibial plateau)
How is no rotation demonstrated for a weight-bearing knee
A bilateral or unilateral knee projection (PA) where the pt’s knees are bent 45° and touch the IR, and the CR angle is 10° caudad.
What is the Rosenberg method
midpoint between knee joints at the level of .5″ distal to the apex of the patellae for bilateral or midpoint of knee joint at level of .5″ below apex of patella if done unilateral
Where is the CR centered for the Rosenberg weight-bearing bilateral knee
An intercondylar fossa PA tunnel view where pt is prone with leg bent 40-50° with the CR caudad with the same degree of angle – 40-50°, depending on what is selected for the flexion.
What is the Camp Coventry Method
To demonstrate interncondylar fossa, femoral condyles, tibial plateaus and intercondylar eminence to show evidence of cartilaginous pathology, osteochondral defects or narrowing of the joint space
When is an intercondylar fossa projection indicated
The Holmblad method
Which projection best demonstrates the intercondylar fossa
the Camp Coventry or a variation (chair or wheelchair) of the Holmblad Method. Also, the BeClere.
What is the most comfortable intercondylar fossa projection
Patient on all fours on table, leaning forward 20-30° so there is a 60-70° flexion. CR is then perpendicular to the IR and lower leg.
What is the Holmblad method
The intercondylar fossa in profile, not superimposed by the patella. Articular facets (tibial plateaus), and knee joint space.
What is well visualized on an intercondylar fossa view
Symmetric appearance of the distal posterior femoral condyles and superimposition of approximately 1/2 of the fibular head by the tibia. The articular facets and intercondylar eminence of the tibia should be well visualized without superimposition.
How is no rotation evident on an intercondylar fossa view
It is a reversal of the PA axial projection for those who cannot assume the prone position. NOT preferred to distortion caused by CR angle, increased part-IR distance.
Another intercondylar fossa projection – AP – where pt is supine and knee is flexed 40-45° with IR under the fossa (stacked on sponges or other stacking devices) with a CR angle of 40-45° cephalad (perpendicular to the lower leg, at .5″ distal to the apex of the patella.)
What is the Beclere method
Increased OID unless a curved cassette is available. Also enhances gonadal exposure. And distortion due to angle of CR. Curved caseette is preferred to reduce part-IR distance.
What is the disadvantage of using the Beclere method
No, due to the air-gap
Is a grid needed with the Beclere method?
5° rotation of knee medially, CR at midpatella area (mid-popliteal crease) – perpendicular
Where is the CR centered for the PA patella
Patella is centered to the femur. Symmetric appearance of the condyles.
How is no rotation evident on a PA patella
No – it may put direct pressure on the patella
Should the pt flex the knee during a PA patella projection?
The AP patella projection
What is the option to the PA patella
Pts knee is in true lateral – with sponge under unaffected knee. Flex knee 5-10°, CR is perpendicular to mid-femoropatellar joint. Femoral epicondyles s/b directly superiimposed and plane of patella perpendicular to the plane of the IR.
Where is the CR centered for the lateral patella
Patient is supine, and use a horizontal beam with no knee flexion
What is the trauma projection for a lateral knee
profile of the patella, open femoropatellar joint. Anterior and posterior borders of medial and lateral femoral condyles s/b directly superimposed and femopatellar jt space s/b open.
What is well visualized on a lateral patella
A tangential (sunrise/skyline) projection with the Pt supine with legs hanging off table, flexed 40° supported with a leg support with a film holder. CR angle is 30° from horizontal, (coming very close to the body) skimming the two knees – centered midway between the patellae
What is the Merchant bilateral Method
To demonstrate subluxation of the patella and abnormalities of the patella and femoropatellar joint
Why is a Merchant bilateral method used
parallel to the tabletop
Knees on a Merchant bilateral should be
48 to 72 inches – increased SID reduces magnification
SID for a Merchant bilateral patella
patient comfort and total relaxation so the quadriceps femoris muscles are relaxed, prevent subluxation of the patellae – may be pulled into the intercondylar sulcus
What is essential for a successful Merchant bilateral
patella and distal femur in profile with the femoropatella jt space open
What is well visualized on a tangential patella
Tangential patella projection where patient is supine, 45° knee flexion with support under knees – pt holding up cassette, CR 10-15° from lower legs, tangential to femorpatellar jt.
What is the inferosuperior patella projection
It doesn’t require special equipment and the positioning is relatively relaxed for the patient. Support provided under knees.
What is the main advantages to the inferorsuperior projection
The pt may have a problem holding up the cassette in the right position
Disadvantage to inferorsuperior patella projection
A tangential patella projection where the patient is prone, thigh and knee on IR, Knee flexed 55°, CR at 15-20° from long axis of lower leg – centered to midfemoropatellar joint. May be done bilaterally or unilaterally.
What is the Hughston method
Prone position may be difficult for some patients and the tech may have difficulty angling the tube (caused by large collimators)
What is the major disadvantage of the Hughston method
Use a 20° flexion instead of a 45° flexion to prevent the patella from being drawn into the groove
What do some authors suggest for the Hughston Method?
A tangential patella projection where the pt is prone (or sitting holding the cassette), with leg flexed a minimum of 90°. CR skims knee from a 15-20° angle (either caudad if prone, or cephalad if pt is sitting)
What is the Settagast Method
True or False: Both sides are generally taken for comparison when doing a tangential patella projection
sunrise or skyline
What is another name for the tangential axial projections of the patella
The acute knee flexion tightens the quadriceps and draws the patella into the intercondylar sulcus, reducing the diagnostic value of the projection
What is the major disadvantage to the Settagast Method
The Hobbs modification – a superoinferior tangential projection
What is the reverse of an inferosuperior patella tangential projection
A tangential projection where the pt is sitting in a chair with feet slightly under the chair. The IR will be on a stool to decrease OID. Knees flexed
What is the Hobbs modification – patella
What is the minimum SID for a Hobbs modification
to mid-femoropatella joint
Where is the CR centered for a Hobbs modification
Patient can be examined while in a chair, and requires little manipulation of the x-ray tube
What is the advantage to the Hobbs
The acute flexion of the knees tightens the quadriceps and draws the patella into the intercondylar sulcus, reducing the diagnostic value of the projection
The disadvantage to the Hobbs
soft tissue surrounding phalanges to distal portion of talus.
open tarsometatarsal joint spaces and visualization of the jt b/w the 1st and 2nd cuneiforms.
What structures are shown for an AP weight-bearing foot
Entire foot with minimum of 1″ of distal tib/fib. Distal fibula s/b/seen superimposed over posterior half of the tibia and plantar surfaces of heads of metatarsals should appear directly superimposed if no rotation is present.
What structures are shown for an lateral weight-bearing foot
distal one-third of lower leg, malleoli,talus and proximal 1/2 of the metatarsals. Make sure to include the base of the 5th metatarsal, a common fracture site.
A 45° oblique demos the tib/fib joint open. The lateral malleolus and talus jt should should no or only slight superimposition, but the medial malleolus and talus will be partially superimposed.
Foot must be flexed only 80-85° (10-15° from vertical) – if more, the calcaneus will be superimposed over the lateral malleolus, obscuring important anatomy.
WHat is shown on a 45° medial oblique ankle
entire tib/fib with both ankle and knee joints (except if follow-up exam). Tibial tuberosity in profile, a portion of proximal head of fibula superimposed by tibia and outlines of the distal fibula seen through the posterior half of the tibia. Posterior borders of femoral condyles should appear superimposed.
What is visualized on a lateral leg
For ankle images, how much of the tib/fib should be visualized
at least 1/2 of the distal metatarsals
For toe images, how much of the metatarsals should be visualized
results in direct superimposition of the distal borders of the femoral condyles.
What does the 5-10° cephalad angle on the lateral knee do
at least 1/2 of the proximal metatarsals
For ankle images, how much of the metatarsals should be visualized
Holmblad and its variations
What are the projections that demonstrate the intercondylar fossa
Hobbs (sitting tangential)
What are the projections that demonstrate the patella sunrise/skyline