A thickening of the anterior capsule extends from the anterior surface of the fibular malleolus, just lateral to the articular cartilage of the lateral malleolus, to just anterior to the lateral facet of the talus and to the lateral surface of the talar neck.
It is an intracapsular structure and is approximately 2–5-mm thick and 10–12-mm long.
The ATFL functions to resist ankle inversion in plantarflexion. Regardless of ankle position, the ATFL is usually the first ankle ligament to be torn in an inversion injury.
It is an extra-articular structure covered by the fibular (peroneal) tendons, is larger and stronger than the ATFL.
It fans out at 10–40 degrees from the tip of the fibular malleolus to the lateral side of the calcaneus, paralleling the horizontal axis of the subtalar joint. This ligament effectively spans the ankle and subtalar joints, which have markedly different axes of rotation.
The ligament is coalescent with the joint capsule, and its orientation is relatively horizontal. Its attachment on the talus involves nearly the entire nonarticular portion of the posterior talus to the groove for the flexor hallucis longus (FHL) tendon, and anteriorly to the digital fossa of the fibula, which transmits the vessels that supply the talus and the fibula.
It is the strongest of the lateral ligament complex, and serves to indirectly aid talofibular stability during dorsiflexion due to its anatomic location, where it can act as a true collateral ligament and prevent talar tilt into inversion.
The PTFL is rarely injured except in severe ankle sprains.
Physical exam: posterior drawer test of the ankle.
Lateral Talocalcaneal Ligament (LTCL):
It’s a 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.
Its function is to stabilize the talocalcaneal joint.
Anterior talofibular ligament (ATFL) is the weakest ankle ligament.
Posterior talofibular ligament (PTFL) is the strongest ankle ligament.
In dorsiflexion, the PTFL is maximally stressed, and the CFL is taut, whereas the ATFL is loose. Conversely, in plantarflexion, the ATFL is taut, and the CFL and PTFL become loose.
Millers Review of Orthopaedics -7E Book
Clinical Tests for the Musculoskeletal System 3rd Ed. Book