Lower limb
Posterior talofibular ligament (PTFL)
Ligamentum talofibulare posterius (PTFL)
- Origin
- Malleolar fossa on the inner side of the lateral malleolus
- Insertion
- Posterior process of the talus
- Function
- Checks dorsiflexion and external rotation of the talus. By far the strongest of the three lateral ligaments, and horizontally oriented.
- Innervation
- Tibial nerve
- Movement & chain
- Nearly always slack, tightening only in maximal dorsiflexion. It therefore does little in daily use and tears only under considerable force.
- Palpation
- Barely reachable: it lies behind the lateral malleolus, deep to the fibular tendons and the Achilles tendon. In practice you project it rather than palpate it.
- Clinical
- Injury here belongs to a severe sprain or an ankle dislocation, and means all three lateral ligaments are torn. Such an ankle is grossly unstable and belongs with the surgeon.
- Segmental innervation
- Segmentally S1-S2
- In clinical practice
- Rarely injured in isolation. When it does come into play, the question is not which ligament but whether the mortise is still intact.
- Region in the model
- Lower limb