Download Radiology

Radiology of LE (21)
Bone
Knee
Description/Pictures
-normal: AP x-ray
-normal: lateral x-ray  useful for assessing soft tissues as well as bones; the quadriceps & patellar
tendons are visible; note the normal suprapatellar pouch between fat pads above the patella
(asterisks)  widening of these fate pads or increased density in this area can indicate a knee joint
effusion
-normal sunrise view (“skyline” view) not usu. indicated in the context of trauma; more helpful to
assess knee pain d/t suspected patellofemoral compartment OA; normal patellofemoral
compartment spacing
-tibial plateau fx- AP view
*fx fragment is displaced & depressed from its normal position (dotted line)
-tibial plateau fx- lateral view
*no visible fx line; depressed tibial plateau contour (arrow); lipohemarthrosis (fat & blood in the
joint)
-normal anatomical variants  A fabella is a normal sesamoid bone of the lateral head of
gastrocnemius tendon - not to be mistaken for a fracture or loose body
-normal anatomical variants  bipartite patella is a common normal variant; note the smooth
edges of each part
*Injury to the interface of the 2 components is possible which may be symptomatic
-Knee MRI- coronal  (1) lateral femoral condyle (2)medial femoral condyle (3) PCL (4) lateral
meniscus (5) medial meniscus (6) tibia (7) fibula (8) ACL (9) LCL (10) MCL
-MRI- sagittal  (1) patella (2) femur (3) infrapatellar fat pad (4) ACL (5) PCL (6) tibia (7) patellar
ligament (8) Quad femoris tendon (9) popliteus
-MRI- axial  1=patella; 2=Lateral condyle of femur; 3=medial condyle of femur; 4=ACL; 5=PCL;
6=LCL; 7=MCL; 8=popliteal artery and vein; 9=popliteus; 10=biceps femoris
Tibia &
Fibula
-Comminuted fx with medial displacement & posterior angulation
-Tibial stress fx  periosteal stress reaction are signs of stress injury (often not present on the
initial XR); hx of chronic pain worsened by activity
-toddler’s fx  a spiral tibial fx seen in young children; associated with a twisting injury and may
present with refusal to weight-bear; often little or no displacement & fx line is very subtle
*some not visible on initial XR but cause a periosteal stress reaction which becomes visible on f/u
Ankle
-normal AP “mortise”  the weight bearing portion is formed by the tibial plafond and the talar
dome; joint extends on the “lateral gutter” and the “medial gutter”  joint evenly spaced
throughout
-Trimalleolar fx- AP & lateral views  (1) medial malleolus fx; (2)lateral malleolus fx  proximal to
the ankle & extending up the fibula [Weber C fx]; (3) posterior malleolus fx
*joint is unstable & widened anteriorly (arrowheads) and the distal tibiofibular syndesmosis
(asterisk)
*talus is displaced posteriorly & laterally along w/the medial & lateral malleolus bone fragments
-abnormal ankle  which ligaments indicated by 1 & 2?  (1) anterior tibiotalar & (2) tibiofibular
-Maisonneuve fx  typical mechanism of action for fracture?
*disruption of the medial ankle joint w/small bone avulsion
*OR disruption of the distal tibio-fibular syndesmosis
*no fibular fx is visible at the ankle raising the suspicion of a proximal fibular fx
*spiral fracture of the proximal fibula
Foot
-osteochondral fracture  talus
-Dorsal-plantar & oblique views
*hindfoot  calcaneus + talus
*midfoot  clavicular + cuboid + cuneiforms
*Forefoot  metatarsals + phalanges
*MC- medial cuneiform
*IC - intermediate cuneiform
*LC- lateral cuneiform
*note the sesamoid bones!
(1)hind-midfoot junction  CHOPART’S JOINTS
(2)mid-forefoot junction  tarsometatarsal joints (TMTJs) = LISFRANC’S JOINT
-ligament anatomy
-abnormal  extremely strong Lisfranc’s ligament runs obliquely from the plantar surface of the
base of the second metatarsal to the plantar surface of the medial cuneiform, and is a major
restraint to midfoot disruption
-anatomic variants  5th metatarsal base fx
*L image - fx line passes transversely across the bone
*R image – a normal unfused 5th metatarsal base apophysis is aligned more longitudinally along
the bone
*what would be a typical hx presentation for a fx like this?
Avulsion- This type of fracture is the result of an injury in which the ankle rolls
Jones fracture- occur in a small area of the fifth metatarsal that receives less blood and is
therefore more prone to difficulties in healing; can be either a stress fracture (a tiny hairline break
that occurs over time) or an acute (sudden) break; caused by overuse, repetitive stress, or trauma;
They are less common and more difficult to treat than avulsion fractures
Pain, swelling, and tenderness on the outside of the foot; Difficulty walking; Bruising may
occur