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Ankle Ultrasound

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Ankle Ultrasound

  • Technique
  • Anterior (dorsal) Ankle
  1. Positioning
    1. Patient lying supine with knee flexed to 90 degrees, foot flat on exam table
  2. View 1: Tibia-Talar Joint in Long Axis (LAX)
    1. Ultrasound probe
      1. Probe in long axis overlying the tibial talar joint, with the probe indicator toward knee and proximal leg
    2. Images
      1. usAnkle_AntLongTibialTalarJoint.png
    3. Components (screen left to right)
      1. Tibia
      2. Joint space
      3. Talus (talar dome)
  3. View 2: Tibia-Talar Joint in Short Axis (SAX)
    1. Ultrasound probe
      1. Rotate probe from LAX (see above) to short axis overlying the joint
      2. Slide or tilt the probe distally (slight movements) from over the tibia onto the talar dome
  • Technique
  • Lateral Ankle
  1. Positioning
    1. Patient lying supine with knee flexed to 90 degrees, foot flat on exam table (same as for anterior ankle)
  2. View 1: Anterior talo-fibular ligament
    1. Ultrasound probe
      1. Probe in short axis overlying distal fibula, with the probe indicator toward posterior ankle
      2. Slide the probe distally from fibula toward talus
    2. Images
      1. usAnkle_LatAtf.png
    3. Components (screen left to right)
      1. Distal fibula
      2. Anterior talo-fibular (ATF) ligament
      3. Talus
    4. Dynamic maneuvers
      1. Invert ankle to evaluate integrity of ATF ligament
  3. View 2: Peroneal Tendons in long axis (LAX) from posterior-lateral approach
    1. Ultrasound probe
      1. Probe in long axis, positioned behind the lateral malleolus and directed posterior to anterior
      2. Probe indicator toward knee and proximal leg
      3. Probe may be rotated 90 degrees (to short axis or SAX) to visualize peroneus tendons in cross section
    2. Components
      1. Peroneus longus (superficial)
        1. Attaches ultimately at first Metatarsal base and medial Cuneiform (lateral aspect)
      2. Peroneus brevis (deeper, immediately deep to longus)
        1. May be followed around lateral malleolus (rotating 90 degrees) to its attachment at fifth Metatarsal head
  1. Positioning
    1. Patient lying supine with knee extended and leg externally rotated
  2. View 1: Tarsal Tunnel in short axis (SAX)
    1. Ultrasound probe
      1. Probe in short axis overlying distal tibia, with the probe indicator toward anterior ankle
      2. Anterior ankle at screen left and posterior ankle at screen right
    2. Images
      1. usAnkle_MedialTransTarsalTunnel.png
    3. Components (Mnemonic: "Tom, Dick and Harry")
      1. Tibialis Posterior tendon (anterior ankle)
      2. Flexor Digatorum tendon
      3. Neurovascular bundle
        1. Posterior tibial veins (several) and one posterior tibial artery
        2. Posterior tibial nerve
      4. Flexor hallucis tendon (posterior ankle)
      5. Tibia (medial malleolus) is deep to these structures
  3. View 2: Tarsal Tunnel in long axis (LAX)
    1. Ultrasound probe
      1. Rotate probe 90 degrees from SAX view (above)
      2. Probe in long axis immediately posterior to medial malleolus (distal tibia)
      3. Probe indicator toward proximal leg (e.g. knee)
    2. Evaluation areas
      1. Slide probe posteriorly to identify these structures
      2. Tibialis Posterior tendon
        1. Most common cause of Tarsal Tunnel (fluid, swelling may be seen on Ultrasound)
      3. Posterior tibial nerve
        1. Lies immediately superficial to the posterior tibial artery
      4. Posterior tibial artery
  • Technique
  • Posterior Ankle
  1. Positioning
    1. Patient lies prone on their Stomache, foot hangs over the end of the bed
  2. View 1: Achilles tendon in long axis (LAX)
    1. Ultrasound probe
      1. Probe in long axis (LAX) overlying the achilles tendon
      2. Probe indicator toward proximal leg (e.g. knee)
      3. Slide Ultrasound probe proximally over the achilles tendon
    2. Images
      1. usAnkle_PostCalfAchilles.png
    3. Components: Insertion at Calcaneus
      1. Achilles Tendon
      2. Retrocalcaneal Bursa
      3. Calcaneous (with insertion of achilles tendon)
    4. Components: Proximal
      1. Achilles Tendon
      2. Gastrocnemius Muscle
        1. Two tracts of Muscle, each with Muscle fiber patterns oriented 90 degrees to one another
      3. Soleus Muscle
      4. Tibia (>7 cm deep)
  3. View 2: Achilles tendon in short axis (SAX)
    1. Ultrasound probe
      1. Probe in short axis (SAX) overlying the achilles tendon (probe 90 degrees to view above)
      2. Slide Ultrasound probe distally over the achilles tendon to its calcaneal insertion
    2. Components
      1. Achilles tendon (superficial, tendon wraps around the Calcaneus)
      2. Calcaneus (deeper)
  4. View 3: Plantar Fascia in long axis (LAX)
    1. Ultrasound probe
      1. Probe in long axis (LAX) overlying the Calcaneus on the plantar foot (slightly medial of center)
      2. Probe indicator facing up toward posterior foot and ankle
    2. Components
      1. Superficial structures
        1. Fat pad
      2. Middle structures
        1. Calcaneus (posterior - left screen)
        2. Plantar fascia (insertion at Calcaneus)
          1. Plantar fascia is normally no more than 4 mm thick at its insertion
      3. Deep structures
        1. Deep dorsiflexion musculature (hypoechoic and may be misinterpreted as fluid)
  • References
  1. Moore (2016) GCUS Musculoskeletal Ultrasound Course, St. Pete's Beach, FL
  2. Moore (2013) Lower Extremity Ultrasound Video, Gulf Coast Ultrasound