The ankle joint has a structurally complex system of ligaments that help to hold the bones in place. On the medial or inside aspect of the joint is the medial/deltoid ligament complex. The lateral or outside aspect consists of the calcaneofibular ligament, the anterior talofibular ligament and the posterior talofibular ligament. The syndesmosis is made up of the the fibrous/ligamentous connections between the tibia and the fibula, providing stability to the ankle mortise. The ankle mortise refers to the structure of the tibia and fibula as a joint surface for the talus by encompassing the talus bone. Common injuries to these ligaments include ankle sprains and fractures.
Function
The ligaments of the ankle help to maintain the structural integrity of the ankle joint. Ligaments are fibrous tissue that connect bones to bones. The bones of the ankle joint include the tibia, fibula, talus, calcaneus and navicular. These bones are linked together by a variety of ligaments. Ligaments can fail, resulting in ankle sprains and fractures.
Anterior Talofibular Ligament
The anterior talofibular ligament (ATFL) is located on the outside or lateral surface of the front of the foot. The ATFL is the most commonly injured ligament in ankle sprains because it is the weakest of the lateral ligaments, according to the "Handbook of Fractures," edited by Dr. Kenneth Koval of Dartmouth University Orthopaedics. The function of this ligament is to support the lateral ankle joint by connecting the talus and the fibula.
Calcaneofibular Ligament
The calcaneofibular ligament attaches the fibula to the calcaneus bone. The ligament has no major role in ankle joint stability, according to the Wheeless' Textbook of Orthopaedics. However, it is considered to be part of the lateral support structure of the ankle joint.
Posterior Talofibular Ligament
The posterior talofibular ligament is the strongest of the lateral support structures. This ligament's primary function is to prevent movement of the talus bone.
Medial/Deltoid Ligament
The medial/deltoid ligament functions to support the inside or medial surface of the ankle. It helps to connect the tibia to the calcaneus, navicular and talus bones. This ligament is separated into two different components: superficial and deep. The superficial component adds little support to the ankle. The deep portion is the primary medial stabilizer of the ankle. Overall, the medial ligament structure is much stronger than the lateral support structures.
Syndesmotic Ligaments
A syndesmosis refers to two bony surfaces that are slightly movable, and are united by ligaments and a membrane between the bones. In the body, this relationship occurs with the tibia and fibula at the ankle joint. The syndesmotic ligaments help to connect the tibia and the fibula and keep them from separating. The ligaments of the syndesmosis include the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, the transverse tibiofibular ligament and the interosseous ligament. These ligaments function to maintain ankle joint stability by maintaining structural support of the ankle mortise.
References
- "AAOS Comprehensive Orthopaedic Review"; Dr Jay Lieberman; 2008
- "Handbook of Fractures (3rd edition)"; Dr Kenneth Koval, Dr Joseph Zuckerman; 2006
- "Expert Guide to Sport Medicine"; Dr. Matthew Davis, Dr Peter Davis, and Dr David Ross (eds); 2005
- "Clinicially Oriented Anatomy (5th edition)"; Dr Keith Moore, Dr Arthur Dalley (eds); 2006
- Wheeless' Textbook of Orthopaedics: Calcaneofibular Ligament
