Ligaments of the Ankle Joint

The ankle joint is medically known as the talocrural joint. Three bones make up this joint; the tibia, fibula, and talus. The weight of the body is transmitted from the tibia to the talus which distributes the weight anteriorly and posteriorly within the foot. Your fibula, that long bone on the outer part of your lower leg, does not bear significant weight through your ankle. It only helps to make up the lateral wall of your ankle joint.

There are four motions of your ankle: dorsiflexion, plantarflexion, inversion, and eversion. Several muscles attach near your ankle and help it move. Your ankle also has ligaments that attach one bone to another. These ligaments help prevent excessive motion around your ankle joint. If you sprain your ankle, one or more of these ligaments become overstretched, leading to ankle pain and limited functional mobility. Repeated ankle sprains can lead to an unstable ankle joint.

The Ankle Ligaments

The two ankle joint groups of ligaments are the lateral collateral ligaments that run on the outside of the knee and medial collateral ligaments that run along the outside of the knee. Although the ankle's ligaments are fibrous solid bands, they are often susceptible to injury due to the excessive movement of the subtalar joint during activity.

The lateral collateral ligaments include the anterior talofibular ligament (ATLF), calcaneofibular ligament (CFL), talocalcaneal ligament (TL), posterior talocalcaneal ligament (PTL) and the posterior talofibular ligament (PTFL). The ATFL function resists inversion and plantar flexion of the ankle joint. The CFL crosses the ankle and subtalar joints, and is the only ligament that spans two separate joints laterally, and is taut in flexion, extension and varus angulation, but relaxes during valgus stress to the ankle. The PTFL has a secondary role in ankle joint stability, also the least commonly injured of the three ligaments. The PTL stabilizes the posterior subtalar joint in the ankle and is a potential source of pain in chronic subtalar instability.

The lateral ankle ligaments are most often sprained. If you turn your ankle inwards forcefully, you may overstretch or tear these ligaments, leading to an ankle sprain.

The medial collateral ligaments, or deltoid ligament (DL), include the tibionavicular ligament (TL), calcaneotibial ligament (CL), anterior talotibial ligament (AT), and the posterior talotibial ligament (PTL). The TL runs anteriorly from the medial malleolus to the navicular bone. The CL runs from the tip of the medial malleolus to the edge of the calcaneus. Both prevent abduction. The anterior and posterior talotibial ligaments run anteriorly and posteriorly between the medial malleolus and the talus. They limit plantar flexion and dorsiflexion respectively.

The DL ligament is a thick ligament, and it is not sprained as easily as the lateral, or outside, ligaments. The fact that your fibula on the outside part of your ankle blocks excessive motion into eversion also creates a situation where overstretching the deltoid ligament is difficult.

Physical Therapy

If you have twisted or turned your ankle, you may have suffered an ankle sprain. You may benefit from physical therapy for an ankle sprain.

Rehab of an ankle sprain involves several components. These may be:

• Control the inflammation and swelling around your ankle
• Perform exercises to improve your ankle range of motion
• Improve calf flexibility
• Improve ankle strength and stability
• Improve balance
• Improve proprioception of your lower extremity

Check in with your healthcare provider if you have sprained your ankle, just to be sure your ankle is not fractured. Then, visit your physical therapist to learn what you should do to treat your ankle sprain. Your PT can help you return to your previous level of activity quickly and safely.