joint_moved.jpg image_moved.jpg flexion_moved.jpg notch_moved.jpg
Ankle Joint Osteology
  • Ankle Joint
    • consists of 
      • tibial plafond
      • medial malleolus
      • lateral malleolus
      • talus
    • motion 
      • main motion 
        • plantar flexion
        • dorsiflexion
      • secondary motions
        • inversion/eversion
        • rotation
  • Distal tibiofibular joint
    • consists of
      • distal fibula
      • incisura fibularis 
        • concave surface of distal lateral tibia
    • motion
      • fibular rotates within incisura during gait
      • mortise widens when ankle goes from plantar to dorsiflexion
      • syndesmosis screws limit external rotation
  • Joint reaction force 
    • ankle joint
      • 5 times body weight with walking on level surfaces
Ankle Ligament Introduction
  • Primary ligaments of ankle include (see below for details)
    • medial
      • Deltoid ligament
      • Calcaneonavicular ligament (Spring Ligament) 
    • lateral
      • Syndesmosis (includes AITFL, PITFL, TTFL, IOL, ITL)
      • Anterior talofibular ligament (ATFL)
      • Posterior talofibular ligament (PTFL)
      • Calcaneal fibular ligament (CFL)
      • Lateral talocalcaneal ligament (LTCL)
  •  Function
    • responsible for integrity of ankle mortise
  • Anatomy
    • Syndesmosis components 
      • Anterior-inferior tibiofibular ligament (AITFL)
      • Posterior-inferior tibiofibular ligament (PITFL)
        • deep portion of this ligament sometimes reffered to as the inferior transverse ligament
      • Transverse tibiofibular ligament (TTFL)
      • Interosseous ligament (IOL)
  • Physical Exam
    • test to identify a syndesmosis injury include
      • external rotation test 
      • squeeze test 
  • Imaging
    • AP and mortise ankle radiographs
      • used to evaluate the tibiofibular clear space and tibiofibular overlap
        • tibiofibular clear space should be < 5 mm
        • tibiofibular overlap for AP view > 10 mm
      • weight bearing mortise view is most accurate radiograph for diagnosis
      • CT scan is most accurate for assessment but true normals have not been validated and comparison to the uninjured side are helpful
  • Clinical conditions
    • high ankle sprain & syndesmosis injury 
    • ankle fracture 
Anterior Talofibular Ligament (ATFL)
  • Function
    • primary restraint to inversion in plantar flexion
    • resists anterolateral translation of talus in the mortise
    • weakest of the lateral ligaments
  • Anatomy 
    • extends from the anteroinferior border of the fibula to the neck of the talus
      • origin is 10mm proximal to tip of fibula
      • inserts directly distal to articular cartilage of the talus (18mm distal to joint line)
      • runs 45°-90° to longitudinal axis of the tibia
  • Physical exam
    • anterior drawer in 20° of plantar flexion
      • test competency by anterior drawer in 20° of plantar flexion and compare to uninjured side
      • forward shift of more than 8 mm on a lateral radiograph is considered diagnostic for an ATFL tear
  • Imaging
    • stress radiographs
      • more accurate in chronic injuries
    • MRI 
      • can diagnose injury 
    • arthroscopic findings 
      • can confirm MRI imaging  
    • ultrasound
      • more accurate than radiographs 
  • Clinical Conditions
    • low ankle sprains 
Posterior Talofibular Ligament (PTFL)
  •  Function
    • strongest of the lateral ligaments
    • plays only a supplementary role in ankle stability when the lateral ligament complex is intact
    • under greatest strain in ankle dorsiflexion and acts to limit posterior talar displacement
      within the mortise as well as talar external rotation
    • if ATFL and CFL are incompetent, then
      • short fibers of PTFL restrict internal and external rotation, talar tilt, and dorsiflexion;
      • long fibres inhibit only external rotation, talar tilt, and dorsiflexion
  • Anatomy
    • origin is posterior border of fibula 
    • inserts on posterolateral tubercle of the talus
    • runs perpendicular to longitudinal axis of the tibia
  • Physical exam
    • no specific clinical test for isolated PTFL injury
  • Imaging
    • MRI can indicate structural injury, rarely indicated
  • Clinical Conditions
    • rarely injured, except in association with a complete dislocation of the talus
Calcaneal Fibular Ligament (CFL)
  • Function
    • primary restrain to inversion in neutral or dorsiflexed position
    • restrains subtalar inversion, thereby limiting talar tilt within mortise
  • Anatomy 
    • origin is anterior border of fibula, 9mm proximal to distal tip
    • inserts on calcaneus 13mm distal to subtalar joint and deep to peroneal tendon sheaths
  • Physical exam
    • inversion (supination) test 
      • perform with ankle in slight dorsiflexion
    • talar tilt test
      • angle formed by tibial plafond & talar dome is measured as inversion force is applied to hindfoot (<5 deg is normal for most ankles)
      • useful for evaluation of combined injury of both ATFL and CFL ligament
  • Imaging
    • talar tilt radiographs 
    • ankle arthrograms
      • CFL rupture can lead to extra-articular dye leakage into the peroneal tendon sheath
    • MRI
  • Clinical Conditions
    • injury occurs with ankle inversion with the foot in the neutral position
    • low ankle sprain 
Lateral Talocalcaneal Ligament (LTCL)
  • Function
    • thought to stabilize the talocalcaneal joint
  • Anatomy
    • short narrow ligamentous band that connects the lateral process of the talus to the lateral surface of the calcaneus
    • located anterior and medial to calcaneofibular ligament
  • Physical Exam
    • no specific test for this ligament
  • Imaging
    • LTCL ligament (red arrows) identified distinctly from the calcaneofibular ligament 
    • relationship of the calcaneofibular ligament (green arrow) and the LTCL (red arrow) 
  • Clinical conditions
    • often injured in conjunction with ATFL injuries
    • low ankle sprain 
Deltoid Ligament
  • Function
    • primary restraint to valgus tilting of the talus
    • both the superficial and deep layers individually resist eversion of the hindfoot
    • stabilizes ankle against plantar flexion, external rotation and pronation
  • Anatomy
    • superficial layer
      • crosses both ankle and subtalar joints
      • originates from anterior colliculus and fans out to insert into the navicular neck of the talus, sustenaculum tali, and posteromedial talar tubercle
      • the tibiocalcaneal (sustenaculum tali) portion is the strongest component in the superficial layer and resists calcaneal eversion
    • deep layer
      • crosses only ankle joint
      • functions as the primary stabilizer of the medial ankle
        • prevents lateral displacement and external rotation of the talus 
      • originates from inferior & posterior aspects of medial malleolus and inserts on medial and posteromedial aspects of the talus
  • Physical exam 
    • eversion test
      • with ankle in neutral, evaluates superficial layer
      • external rotation stress test evaluates syndesmosis and deep layer
  • Imaging
    • radiographs
      • mortise radiograph with medial clear space widening can suggest injury 
      • gravity stress view can identify medial clear space widening 
    • MRI
      • normal deltoid ligament 
      • ruptured deltoid ligament 
  • Clinical conditions
    • ankle fracture 
      • injury occurs with pronation (eversion) trauma leading to forced external rotation and abduction of ankle
      • may occur with fracture of the medial malleolus
    • high ankle sprain & syndesmosis injury 
Calcaneonavicular Ligament (Spring Ligament)

Please rate topic.

Average 4.5 of 17 Ratings

Questions (1)

(OBQ08.33) A 35-year-old man is referred to you for left foot pain after falling from a bicycle. A recent MRI shown in Figure A. The injured structure demonstrated in the MRI will most likely lead to which of the following deformities if left untreated? Review Topic


Syndesmotic widening




Flatfoot deformity




Widening of the 1st and 2nd tarsometatarsal joints




Hallux valgus deformity




Talar tilt deformity



Select Answer to see Preferred Response


Figure A demonstrates a disrupted calcaneonavicular ligament (Spring ligament). Chronic deficiency of this structure can lead to a flatfoot deformity.

The ability of the medial longitudinal arch to prevent flatfoot deformity depends on the dynamic support of the posterior tibial tendon, the static support of ligaments and capsule (including the Spring ligament), and the manner in which the tarsal bones interlock.

Gadzag retrospectively found that 18 of 22 patients undergoing surgery for flatfoot deformity had varying levels of injury to the spring ligament but their study design prevented them from concluding whether ligament repair was beneficial.

Illustration A contains an MRI of a normal Spring ligament (right) shown with a green arrow compared to a disrupted Spring ligament (left) shown with the red arrow. Illustration B is a cadaveric dissection showing the spring ligament (5) once the posterior tibial tendon (9) has been reflected.


Please rate question.

Average 4.0 of 26 Ratings

Question COMMENTS (5)
Sorry, this question is available to Virtual Curriculum members only.

Click HERE to learn more and purchase the Virtual Curriculum today!

This is a Never-Been-Seen Question that can only be seen in Milestone Exams
for Virtual Curriculum members.

Click HERE to learn more and purchase the Virtual Curriculum today!

Topic COMMENTS (15)