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 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 becomes overstretched, leading to ankle pain and limited functional mobility. Repeated ankle sprains can lead to an unstable ankle joint.
The Ankle Ligaments
The ligaments of the ankle joint are grouped into two categories: the lateral collateral ligaments and the medial collateral ligaments. Although the ligaments of the ankle are strong fibrous 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, calcaneofibular ligament, talocalcaneal ligament, posterior talocalcaneal ligament and the posterior talofibular ligament. The anterior talofibular ligament passes from the tip of the lateral malleolus to the talus anteriorly. It limits plantar flexion of the joint. The calcaneofibular ligament passes from the lateral malleolus to the calcaneus with the talocalcaneal ligament running at its base. They resist adduction. The posterior talofibular ligament passes from the tip of the lateral malleolus to the talus posteriorly. The posterior talocalcaneal extends this band to the calcaneus. Both limit dorsiflexion.
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, include the tibionavicular ligament, calcaneotibial ligament, anterior talotibial ligament, and the posterior talotibial ligament. The tibionavicular ligament runs anteriorly from the medial malleolus to the navicular bone. The calcaneotibial ligament 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 deltoid 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.
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 proprioception of your lower extremity
Check in with your doctor 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.