Transcript Radiographic Critique of the Lower Extremity

Radiographic Critique
of the Lower
Extremity
Chapter 5
Foot (AP-Dorsoplantar)
 ID requirements /marker /No preventable
artifacts
 Contrast & density: soft tissue & bony
structures of foot
 Good penetration trabecular & cortical of
phalanges, metatarsals & tarsals
(55-65kVp)
Foot (AP-dorsoplantar)
 ?true AP: 1st, 2nd, & 3rd cuneiforms joints
spaces open; with 2cm of calcaneus shown
without talar superimposition and equal
concavity on both sides of 1st metatarsal
midshaft
 ?leg, ankle, and foot aligned
 ? Rotated laterally the navicular tuberosity is
shown in profile with the talus over the
calcaneus
 ? Rotated medially talus moves away from
calcaneus
Foot (AP-dorsoplantar)
 ? Tarsometatarsal & navicular-cuneiform
joint space open
 ?long axis aligned
 ? Proximal 2nd & 3rd metatarsal bases in
center of field with proximal calcaneus,
talar neck, tarsals, metatarsals,
phalanges, & surrounding foot soft tissue
Foot (medial or internal)
oblique position
 Determine ? Obliquity ( 30 or 45 degrees)
 Low arch 30 degrees / high arch 45 degrees
 ?not rotated enough, 4th & 5th intermetatarsal
joint spaces are closed with 4th met base
superimposed 5th
 ?rotated too much, 4th & 5th intermetatarsal
joint space is closed with 5th proximal met base
superimposed 4th
 ?long axis aligned/ 3rd met base in center of
field
Foot (lateral)
 ?true lateral: domes of talus are
superimposed, the tibiotalar joint is open &
distal fibula is superimposed by the posterior
half of the distal tibia
 ? Long axis of foot at 90 degree angle with
lower leg and aligned with long axis
 ?proximal metatarsals in center of field with
phalanges, metatarsals, tarsals, talus,
calcaneus, 1 inch of distal lower leg
Ankle (AP)
 If rotated laterally or medially the medial
mortise is hidden
 ?tibiotalar joint open & tibia seen without
foreshortening
 ?long axis of tibia aligned
 ?tibiotalar joint in center of field with
distal 4th of tibia & fibula, talus and soft
tissue on film
Ankle (Medial- internal
oblique)
 ID requirements / marker / no preventable artifacts
 Contrast & density with good penetration
 ?adequate obliquity: distal fibula seen without talar
superimposition, with an open lateral mortise, also
lateral & medial malleoli in profile
 ?tibiotalar joint open and tibia seen without
foreshortening
 ?calcaneus seen distal to lateral mortise and fibula
 ?long axis of tibia aligned
 ?tibiotalar joint in center of field
Ankle ( lateral)
 ?true lateral
 ?domes of talus superimposed
 ?tibiotalar joint open with distal fibula
superimposed by the posterior ½ of distal tibia
 ?long axis of foot at 90 degree angle with lower
leg
 ?long axis of tibia aligned
 ?tibiotalar joint at center of field showing talus,
1 inch of 5th metatarsal base, soft tissue and
distal ¼ of fibula and tibia on film
Knee (AP)
 ?femorotibial joint open
 ?anterior and posterior condylar margins of tibia
superimposed
 ?intercondylar eminence and tubercles are seen in
profile
 ?fibular head seen distal to tibial plateau
 ?patella lies superior to patellar surface of femur and is
lateral to knee midline
 ?intercondylar fossa partially seen
 ?femorotibial joint is in center of field with ¼ of distal
femur & proximal lower leg with soft tissue on film
Knee (medial & lateral
oblique)
 ID requirements / marker / no preventable artifacts
 Contrast & density with good penetration
 60 to 70 kVp for knee thickness under 5 inches( don’t
need grid)
 Above 70 kVp for thicker knees for use of grid
 ?femorotibial joint open; anterior & posterior condylar
margins of tibia are superimposed with fibular head
distal to tibial plateau
 ?femorotibial joint in center of field with ¼ of distal
femur & proximal lower leg on film
Knee (medial oblique)
 ?rotated 45 degrees medially
 This places the lateral condyle in profile
and rotates the fibular head from beneath
tibia
 Too much-femoral condyles are almost
superimposed
 Not enough-tibia slightly superimposes
the fibular head
Knee (lateral oblique)
 ?rotated 45 degrees laterally
 This places the medial condyle in profile and
rotates the tibia onto the fibula
 Not enough-fibular head is seen in center of
tibia
 Too much – fibular head is aligned with the
posterior edge of the tibia and the femoral
condyles are almost superimposed
Knee (lateral)
 ID requirements / marker / no preventable artifacts
 Contrast & density with good penetration
 ?knee flexed 10 to 15 degrees with patella proximal to
patellar surface of the femur and patellofemoral joint
open
 ?distal joint surfaces of medial & lateral femoral
condyles superimposed with the femorotibial joint
space open
 ?anterior & posterior surfaces of the medial & lateral
femoral condyles superimposed with tibia slighlty
superimposing fibular head
 ?femorotibial joint in centr of field