[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/) › CFL [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # CFL The calcaneofibular ligament runs from the outer ankle bone down to the heel; it tears in more severe ankle sprains. Official name: Calcaneofibular ligament [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=lower_limb&select=cfl&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A cord-like ligament on the outer ankle, from the tip of the [fibula](https://durgical.com/en/anatomy/fibula/) down to the heel bone. ## What it does Steadies both the ankle and the joint below it (the subtalar joint) when the foot rolls inward. ## Key points - The only lateral ankle ligament that crosses two joints (ankle and subtalar), so a tear can loosen both - Lies outside the [joint capsule](https://durgical.com/en/anatomy/articular-capsule-of-knee-joint/), right under the sheath of the fibular tendons: a CFL tear often opens that sheath - Tested with the talar tilt (inversion stress) with the ankle in neutral or slight dorsiflexion ## Key facts **Attaches** Tip of lateral malleolus to lateral surface of calcaneus, deep to fibularis tendons **Function** Resists inversion; stabilizes ankle and subtalar joints; second ligament torn in sprains **Tight in** Dorsiflexion with inversion ## Relations **Course** From the front of the tip of the lateral malleolus downward and backward to a small tubercle on the lateral [calcaneus](https://durgical.com/en/anatomy/calcaneus/), behind the fibular trochlea **Superficial** [Fibularis longus tendon](https://durgical.com/en/anatomy/tendon-of-fibularis-longus/) and [fibularis brevis tendon](https://durgical.com/en/anatomy/tendon-of-fibularis-brevis/) in their common sheath, held by the [fibular retinacula](https://durgical.com/en/anatomy/superior-fibular-retinaculum/); the [sural nerve](https://durgical.com/en/anatomy/sural-nerve/) and [small saphenous vein](https://durgical.com/en/anatomy/small-saphenous-vein/) run further back **Deep** Lateral [talus](https://durgical.com/en/anatomy/talus/) and the posterior subtalar joint, with the thin [lateral talocalcaneal ligament](https://durgical.com/en/anatomy/lateral-talocalcaneal-ligament/) **In front** [ATFL](https://durgical.com/en/anatomy/anterior-talofibular-ligament/), which arises just above and in front of it ## How to find it Just below the tip of the lateral malleolus, under the fibular tendons; it is felt as a firm cord when the foot is turned in with the ankle at a right angle. ## Examination - Talar tilt: heel held, talus and calcaneus inverted with the ankle in neutral; more tilt than the other side, or a soft endpoint, suggests a CFL tear (usually with the ATFL) - Resisted eversion with pain behind the malleolus points to the fibular tendons rather than the CFL ## On imaging Inversion stress X-rays (talar tilt) compared with the other ankle; ultrasound shows it lifting the fibular tendons when the foot dorsiflexes; MRI (coronal and axial) shows it as a dark band deep to the tendons. In the past, contrast leaking from the ankle joint into the fibular tendon sheath on arthrography meant a CFL tear. ## Common problems - Torn in more severe ankle sprains, usually after the ATFL. - Chronic instability if it heals loose. - The fibularis tendons run right over it and can be injured at the same time. ## How it is diagnosed A physical exam (tenderness, talar tilt test). X-rays rule out a fracture. MRI or ultrasound for ongoing problems. ## Treatment - Most sprains heal without surgery: rest, ice, compression, a brace or boot, then balance and strengthening exercises. - Chronic instability: surgery to repair and tighten the ligament. - If the ligament tissue is poor: reconstruction with a tendon graft from the patient or a donor. ## Clinical notes - Combined ATFL and CFL tears can leave both ankle and subtalar instability, which are hard to tell apart on examination - Fibular tendon tears and tendon sheath problems often coexist with CFL injury and are a common cause of pain after a 'simple' sprain - The sural nerve and fibular tendons lie close by and are at risk in lateral ligament reconstruction ## Anatomical variants - Its angle to the fibula varies widely between people, from nearly vertical to sloping well backwards - The lower band of the ATFL is often linked to its origin by arching fibres, so the two can work as one lateral complex ## Related conditions - [Lateral Ankle Sprain](https://durgical.com/en/conditions/lateral-ankle-sprain/) ## Test yourself Think of the answer, then tap the question to see it. ## Where does the calcaneofibular ligament (CFL) attach? From the tip of the lateral malleolus to the lateral surface of the calcaneus, deep to the fibular tendons. ## Why can a calcaneofibular ligament tear loosen two joints? It is the only lateral ankle ligament crossing two joints: the ankle and the subtalar joint. ## Which test assesses the calcaneofibular ligament? The talar tilt (inversion stress) with the ankle in neutral or slight dorsiflexion. ## Which tendons lie directly over the calcaneofibular ligament and are often injured with it? The fibularis longus and brevis tendons in their common sheath. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/calcaneofibular-ligament/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ligamentum calcaneofibulare TA2 1921 **Official Spanish (DeCS)** Ligamento calcaneofibular DeCS D017844 **English (TA2)** Calcaneofibular ligament **Also called** ligamentum fibulocalcaneare ## Related - [ATFL](https://durgical.com/en/anatomy/anterior-talofibular-ligament/) - [PTFL](https://durgical.com/en/anatomy/posterior-talofibular-ligament/) - [Fibularis longus tendon](https://durgical.com/en/anatomy/tendon-of-fibularis-longus/) - [Fibularis brevis tendon](https://durgical.com/en/anatomy/tendon-of-fibularis-brevis/) - [Calcaneus](https://durgical.com/en/anatomy/calcaneus/) - [Fibula](https://durgical.com/en/anatomy/fibula/) 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/calcaneofibular-ligament/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/calcaneofibular-ligament/