[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) › PTFL [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # PTFL The posterior talofibular ligament is the strongest ligament of the outer ankle, at the back; it is rarely torn. Official name: Posterior talofibular ligament [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=lower_limb&select=ptfl&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A thick ligament at the back of the outer ankle, from the [fibula](https://durgical.com/en/anatomy/fibula/) to the talus. ## What it does Keeps the talus from slipping backward. It is the strongest of the three outer ankle ligaments. ## Key points - Thickest and deepest of the three lateral ligaments; it runs almost horizontally and is torn mainly in ankle dislocations - It anchors on the lateral tubercle of the talus, which may be a separate bone (os trigonum) or a long Stieda process: a cause of posterior ankle impingement - Tightest in dorsiflexion, the opposite of the [ATFL](https://durgical.com/en/anatomy/anterior-talofibular-ligament/) ## Key facts **Attaches** Malleolar fossa of fibula to lateral tubercle of posterior process of talus **Function** Strongest lateral ligament; resists posterior displacement and external rotation of talus **Tight in** Dorsiflexion ## Relations **Above** Posterior inferior tibiofibular ligament and its deep transverse part, just above it **Medial** [Flexor hallucis longus](https://durgical.com/en/anatomy/flexor-hallucis-longus/) tendon in its groove between the lateral and medial tubercles of the [talus](https://durgical.com/en/anatomy/talus/) **Behind** [Fibularis longus](https://durgical.com/en/anatomy/fibularis-longus-muscle/) and brevis tendons behind the lateral malleolus; further back, Kager's fat pad and the [Achilles tendon](https://durgical.com/en/anatomy/calcaneal-tendon/) **Below** CFL, which arises lower down and further forward on the lateral malleolus ## How to find it Not palpable: it lies deep, behind the ankle joint. It is seen through posterior ankle arthroscopy or on MRI. ## Examination - Forced passive plantarflexion test: pain at the back of the ankle suggests posterior impingement (os trigonum or Stieda process) rather than a PTFL injury ## On imaging On axial MRI it normally looks striped (fibres separated by fat); that pattern is not a tear. A lateral X-ray shows an os trigonum or a long lateral tubercle at its attachment. ## Common problems - Rarely torn, except in ankle dislocations. ## Clinical notes - Torn in frank dislocations and in the most severe inversion injuries, together with the ATFL and CFL - Posterior impingement in ballet dancers and footballers: the lateral tubercle or os trigonum is pinched between the [tibia](https://durgical.com/en/anatomy/tibia/) and [calcaneus](https://durgical.com/en/anatomy/calcaneus/) in full plantarflexion - The posterolateral arthroscopy portal lies near the [sural nerve](https://durgical.com/en/anatomy/sural-nerve/) and [small saphenous vein](https://durgical.com/en/anatomy/small-saphenous-vein/) ## Anatomical variants - A posterior intermalleolar ligament, lying between this ligament and the inferior [transverse ligament](https://durgical.com/en/anatomy/transverse-ligament-of-knee/), is common and can be trapped in posterior impingement ## Development The lateral tubercle of the talus ossifies from its own centre in late childhood; if it never fuses, it remains a separate os trigonum, which can be mistaken for a fracture. ## Test yourself Think of the answer, then tap the question to see it. ## Where does the posterior talofibular ligament (PTFL) attach? From the malleolar fossa of the fibula to the lateral tubercle of the posterior process of the talus. ## In which ankle position is the posterior talofibular ligament tightest? Dorsiflexion, the opposite of the ATFL. ## When is the posterior talofibular ligament usually torn? Mainly in ankle dislocations; it is the strongest of the three lateral ligaments. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/posterior-talofibular-ligament/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ligamentum talofibulare posterius TA2 1920 **Official Spanish (DeCS)** Ligamento talofibular posterior DeCS D017844 **English (TA2)** Posterior talofibular ligament **Also called** ligamentum fibulotalare posterius · oblique ligament of Walther ## Related - [ATFL](https://durgical.com/en/anatomy/anterior-talofibular-ligament/) - [CFL](https://durgical.com/en/anatomy/calcaneofibular-ligament/) - [Fibula](https://durgical.com/en/anatomy/fibula/) - [Talus](https://durgical.com/en/anatomy/talus/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=31367&filter=ths_termall&q=Ligamentos%20Laterales%20del%20Tobillo); [Anatomy, Bony Pelvis and Lower Limb: Ankle Joint](https://www.ncbi.nlm.nih.gov/books/NBK545158/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/posterior-talofibular-ligament/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/posterior-talofibular-ligament/