The talocrural joint is the joint that allows you to jump, push off when walking and, in general, move at this particular joint. The joint itself is quite durable for the simple fact that the ligaments of the talocrural joint can be torn in such as fashion as to break the bone.
When the ankle is turned severely, the ligaments are so strong that often they pull the tip of the fibula off, break the medial aspect of the tibia and also can break a third bone, which we will discuss.
The subtalar joint: the subtalar joint is a joint of the ankle, which is often overlooked. This joint allows the heel to turn in and out. The pronation and supination of the foot begins with this varus and valgus motion of the heel and as such, is an important part of balance, agility and accommodation of uneven surfaces such as grass, mud and dirt.
Farming, for instance, would be extremely difficult without the subtalar joint to accommodate dirt clods, furrows and holes in the ground. The subtalar joint turns in and turns out, as the surface changes allowing the body to use the muscles on the inside and outside of the leg to control the in and out motion of the heel.
Combining the subtalar joint in the talocrural joint we have something akin to a universal joint in a car in which it both turns and twists allowing for a variety of motions of the foot and ankle complex.
Add this to the 26 bones of the foot and we have a rather mobile and articulating structure that is able to accommodate many surfaces without harm.
The third joint of the ankle, which is often not discussed is the tibiofibular joint. The inferior tibiofibular joint is the syndesmosis where the tibia joints the fibula and is connected by fibrous connective tissue. The syndesmotic ligaments deform only slightly, but jut enough to allow the tibia and fibula to spread apart, which allows extreme dorsiflexion (up motion) as well as rotation of the lower leg during dorsi and plantar flexion mobility. This joint is sometimes sprained and referred to as a “high” ankle sprain.
The ankle is a complex and wonderful joint that allows us to ac-commodate to a variety of surfaces, allows lower extremity muscles to provide balance and coordinated movements and allows jumping, push off and balance and standing.
Without the cooperation of these three joints the ankle would be nothing more than a single plane articulation and the likelihood of increased falls would be great as most of us would not be able to stand on for instance a moving boat or an uneven surface. When the ankle accommodates to these activities, it is a work of art."
(Dr. Mark McDonald, PT, DPT, OCS is a lifelong resident and board certified orthopedic physical therapist with 21 years practice in Sterling. He is a clinical partner with AB Fitness, Devonshire Acres, and Northeast Plains Home Health Care.) Published in the South Platte Sentinal, Sterling, Colorado.