Ankle Diagnostic Imaging Flashcards
Standard AP - lateral malleolus is ____ compared to medial
Longer
Foot is divided into
3 pieces
Hindfoot
Midfoot
Forefoot
At birth
calcaneus and talus are ossified (cuboid sometimes)
Centers of ossification appear when
btw 1 and 4 yrs
Foot is fully ossified when
about 20 yrs old
Ankle - Routine projections
AP
AP mortise = Oblique
Lateral
In addition inversion and eversion stress projections can be done
AP
Distal tibia and fibula
Medal and lateral malleoli (lateral should be lower than medial)
Head of talus
The bones of the foot are superimposed on each other
In a straight AP projection what overlaps
talus and malleoli
and there is not a clear joint line for talocrural joint
Shaft of tibia and fibula are overlapped too - so no interosseous membrane seen
AP Mortise/Oblique
The leg is rotated to position the malleoli in the same plane (15 deg IR)
View of entire ankle mortise with central beam btw the malleoli
Structures of foot are superimposed again
Ankle mortise =
talocrural joint
third malleolus
post rim of the tibia
Lateral view
Medial to lateral beam direction with lateral aspect closest to the film
Looking at relationship btw tibia and talus
Subtalar articulation
Talus and calcaneus
Zone of neutrality
not that much density in this area - more radiolucent - not as much trabeculae
Below talus on calcaneus
Oblique
limb is externally rotated about 45 degrees Distal tibiofibular area Talofibular joint Lateral malleolus Tarsals are superimposed
Bohler’s angle
btw 20 and 40
Smaller than 20 = injury to calcaneus
Gissaines angle
integrity of talocalcaneal joint (40-50 degrees)
Foot routine projections
AP
Oblique
Lateral
Ray
Tarsal, MT, Phalanges
Foot - AP
Medial 2 rays Phalanges Stress films Foot is positioned flat on receptor Beam from dorsal to plantar - centered in base of 3rd metatarsal
Oblique - foot
45 degrees from the AP, 1st metatarsal against film (kind of pronated)
central ray directed through base of 3rd to 5th rays including phalanges
Lateral - foot
Lateral portion of foot closest to the film
Talar/calcaneal relationship
jones fracture
tuberosity of 5th metatarsal
difference btw lateral of ankle and lateral of foot
where the central ray is position
Ankle = lateral malleolus
Foot = tarsal bone (navicular)
Talometatarsal angle
Arch of foot line along midshaft of metatarsal Line bisectng the talus Normal = straight line WB vs NWB
