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