Ankle/Foot Radiology Flashcards
Foot at birth
calcaneus and talus ossified
at what age do centers of ossification appear in the foot?
age 1-4
when is the foot fully ossified?
age 20
routine projections of the ankle
AP, lateral
Oblique = AP mortise
INV/EV stress projections may also be done
AP of ankle
distal tibia and fibula
medial and lateral malleoli (lateral lower than medial)
head of talus
bones of foot will be superimposed
lines from tibia and talus should be parallel to each other
AP Mortise/Oblique ankle
leg is rotated to position the malleoli in the same plane (15 degrees IR)
Lateral ankle
beam goes from medial to lateral lateral aspect closest to film relationship of tibia to talus subtalar articulation talus and calcaneus
routine projections of the foot
AP, oblique, lateral
AP projection of foot
medial 2 rays
phalanges
stress films
Oblique of foot
45 degrees from AP, 1st metatarsal against film
3rd thru 5th rays including phalanges
Central ray goes thru 3-5th MTs
Lateral of foot
lateral portion of foot closest to film
talar/calcaneal relationship
posterior rim of 3rd malleolus visible
subtalar joint line should be smooth
Talometatarsal angle
line along midshaft of metatarsal
line bisecting talus
normal is a straight line (A)
WB vs NWB
AP inversion and eversion stress projections
ankle mortise joint space is viewed
normal: INV = 5-15 degrees, EV = 10 degrees
Ottawa ankle rules
cannot bear wt/walk 4 steps OR
bony tenderness localized to posterior edge or inferior tip of lateral malleolus
bony tenderness up to 6 cm above either malleolus
Ottawa Mid-Foot rules
cannot bear wt/walk 4 steps
bony tenderness over navicular OR
bony tenderness over base of 5th metatarsal
AP of ankle
foot = big white blob because bones are superimposed on each other
“conditions of distal tibia and fibula” refer to medial and lateral malleolus
talus and malleoli overlap in straight AP
shaft of tibia/fibula overlap
AP mortise (oblique)
IR of leg to get malleoli in same plane
central beam goes thru malleoli
problem if tibia and fibula are separated
zone of neutrality
calcaneus
bone not as dense, not as much trabeculi
fracture = density in this area
normal = radiolucent
Bohler Angle
normal = 20-40 degrees
indicates the calcaneus is intact
below 20 degrees = issue with calcaneus (injury)
Gissane’s Angle (?)
integrity of talocalcaneal joint
normal = 40-50 degrees
AP of foot
ray = metatarsal, tarsal, phalanges
medial 2 rays clearly visible
AP of foot
cuneiforms should line up with metatarsals (not lined up as clearly in oblique view)
AP of Ankle
talus and malleoli should overlap
shaft of tibia and fibula overlap significantly
will not see clear jointline of talocrural joint
interosseous membrane not clearly seen
AP mortise of ankle
central beam goes through malleoli med/lat malleolus clearly visible should have visible talocrural joint space dome of talus visible interosseous membrane clearly seen some MT's visible posterior rim of tibia = 3rd malleolus
