Anatomy of the Ankle
Have you ever heard someone say, “I’ve broke my ankle like 3 times.” This misconstrued diagnosis always makes me wonder if the person saying it didn’t read the documentation or the doctor didn’t explain things very well. I understand that not everyone cares what exact bone was fractured and what type of fracture it was etc. But when I hear this statement it always gets me thinking; what sport(s) were you playing when those injuries occurred? Are you currently playing that sport(s) or have you stopped? Did you receive proper rehabilitation after each instance? Are you taking the proper preventative measures each day to minimize your risk of further injury? Yes, typical athletic trainer, I apologize, but the last thing I’m the most intrigued about is what part of the ankle was affected.
The “ankle” is actually a series of joints that work to provide static support of the most distal part of the lower extremity. That is why I am always curious as to what specific structure was involved when someone says that to me. To break it down a little bit, the foot is divided up into three zones: rearfoot (talus and calcaneus), midfoot (navicular, cuboid, cuneiforms), and forefoot (metatarsals, phalanges), which add up to a total of 26 bones! These bones act as the structural base for our entire body. But for us to move efficiently we need to have adequate range of motion (ROM). In the foot and ankle, the combination of joints allows us to have various types of motion, including; plantarflexion, dorsiflexion, inversion, eversion, abduction and adduction, (at the phalanges) and circumduction. So, let’s talk about the major joints of the ankle, there are four: distal tibiofibular, talocrural, subtalar and transverse tarsal.
The first joint, most proximally is the distal tibiofibular joint. It is a syndesmotic joint, which means there is no movement at the joint and it is joined by connective tissue, in this case the tibia and fibula. The main static stabilizers of this joint are the anterior and posterior tibiofibular ligaments and interosseous membrane. Since this joint is not moveable, it takes a high amount of force for it to be injured and is very uncommon.
The next two joints are the main articulations for the “ankle,” the first being the talocrural joint, which is made up of the tibiotalar and tibiofibular complexes. It is a synovial hinge joint, which means it’s responsible for dorsiflexion and plantarflexion, or bringing the foot up and pushing it down. The talocrural joint forms the ankle mortise, where the fibula, tibia and talus all meet to create the hinge. This joint relies on static support from the lateral ankle complex (anterior/posterior talofibular ligaments and calcaneofibular ligaments) and the medial ankle ligaments or “deltoid” complex (anterior/posterior tibiotalar, tibionavicular and tibiocalcaneal. Yes, I know that sounds like a mouthful, and it is, but these two ligament complexes are the two most commonly injured in ankle sprains. Eighty-five percent of all ankle sprains are lateral ankle sprains, 10-14% are medial ankle sprains and the remaining 1% consist of syndesmotic or high ankle sprains.
The other substantial joint I referred to is the subtalar joint. It is a plane synovial joint which mainly allows for inversion, eversion and some gliding. It is supported by the medial, lateral and posterior talocalcaneal ligaments and the interosseous talocacalneal ligament, which binds the talus and calcaneus together. This joint is very important in allowing your foot to adjust to uneven terrain while moving by shifting from side to side. It is also very important in athletic movements such as pivoting or turning with a fixed foot. This movement is essential for proper gait, but can lead to increased risk of injury if excessive laxity in this joint becomes present, which can lead to hypermobility and overpronation.
The final joint of the ankle is the transverse tarsal joint. This joint involves a slew of bone articulations and ligaments. It is distal to the previous three joints we have talked about and is located near the midfoot. It is a synovial joint and assists the subtalar joint in inversion and eversion of the foot. The ligaments that support this joint include: the long and short planar ligaments, the “spring” ligament (which plays a vital role in arch type), calcaneonavicular ligament and calcaneocuboid ligament.
As you can see there are dozens and dozens of bones, ligaments and tendons in the foot and ankle (many of which we didn’t even get into today). My goal for this article is to introduce you into the basic anatomy of the ankle joint. Take an interest in your body and your injuries, because the more knowledge you have, the more informed decisions you will be able to make in regard to your health care. If you have any questions about the anatomy of the ankle joint or injuries that you may have sustained in training, athletics or in your everyday activities, please reach out, and I encourage you to always #HealByMoving.