What are the ligaments of the ankle and foot?

Ligaments of the Ankle and Foot

Lateral Ligament Complex

The lateral collateral ligament complex is the most frequently injured ligamentous structure in the ankle, with the anterior talofibular ligament (ATFL) being the single most commonly injured ligament in ankle hyperinversion injuries. 1

• The lateral ligament complex consists of three primary ligaments:

  • Anterior talofibular ligament (ATFL): Most commonly injured in inversion ankle sprains, accounting for the majority of lateral ankle injuries 1, 2
  • Calcaneofibular ligament (CFL): Second most commonly injured lateral ligament 3
  • Posterior talofibular ligament (PTFL): Least commonly injured of the lateral complex 3

• Lateral ankle sprains represent 25% of all musculoskeletal injuries and 50% of sports-related injuries 1

• The ATFL is specifically tested with the anterior drawer test, which detects excessive anterior displacement of the talus onto the tibia 1, 2

Medial Ligament Complex (Deltoid Ligament)

The deltoid ligament provides medial stability and consists of both superficial and deep layers 4:

• Superficial layer components:

  • Anterior tibiotalar ligament 2
  • Tibiocalcaneal ligament (TCL): Provides substantial stabilizing effect against supination/inversion, particularly important when lateral ligament instability exists 4
  • Posterior tibiotalar ligament 2

• The deltoid ligament complex plays a critical role in lateral stabilization when lateral ligament injuries are present, with the TCL being particularly important in preventing chronic instability 4

Syndesmotic Ligament Complex (High Ankle Sprain)

The syndesmotic ligaments stabilize the distal tibiofibular joint and are injured in 1-11% of all ankle sprains, with a much longer recovery period than lateral ankle sprains. 5, 6

The syndesmotic complex consists of four primary ligaments 6, 7:

• Anterior inferior tibiofibular ligament (AITFL): Prevents lateral displacement of the fibula 5
• Posterior inferior tibiofibular ligament (PITFL): Provides posterior stability 5, 6
• Transverse ligament: Additional posterior stabilizer 6
• Interosseous ligament: Connects tibia and fibula throughout their length 5, 6

Key Clinical Distinctions

• Syndesmotic injuries occur through dorsiflexion-eversion-external rotation mechanisms, distinctly different from lateral ankle sprains (inversion injuries) 8, 2, 5

• The crossed-leg test (squeeze test) detects syndesmotic injury: pain in the syndesmosis area when pressure is applied to the medial side of the knee 8, 2

• External rotation stress is the most common mechanism, causing widening of the ankle mortise 5, 7

• Syndesmotic injuries occur in approximately 50% of Weber B fractures and all Weber C ankle fractures 6

Clinical Pitfalls to Avoid

Do not confuse lateral ankle sprains with high ankle (syndesmotic) sprains—they have different mechanisms, examination findings, and significantly different recovery timelines. 8, 1

• Widening of the ankle mortise by just 1 mm decreases tibiotalar joint contact area by 42%, leading to instability and early osteoarthritis 6

• Delayed examination at 4-5 days post-injury optimizes sensitivity (84%) and specificity (96%) for detecting complete ATFL ruptures using the anterior drawer test 8, 2

• The presence of all four findings (swelling, hematoma, pain on palpation, positive anterior drawer test) indicates 96% likelihood of lateral ligament rupture 8, 2