You may have noticed that many of your clients are blissfully unaware of just how much work the foot and ankle complex does—unless and until, of course, an ankle sprain or tendinitis occurs. The ankle “negotiates” ground reaction forces, informing the kinetic chain in numerous ways. Among other functions, the feet and ankles help the body adapt to uneven terrain through side-to-side movement (Price 2008).
Twenty-eight bones make up 33 joints in the ankle and foot (Physiopedia 2018). The subtalar joint—also known as the talocalconeal joint—lies between the talus and calcaneus. The talus has three facets (anterior, middle and posterior), which articulate inferiorly with the calcaneus (Physiopedia 2018). According to podiatrist Catherine Moyer (2017), when you sing “The heel bone’s connected to the ankle bone,” you’re singing about the subtalar joint.
Understanding the basics of this joint, along with the entire foot and ankle, will help you assess and address mobility issues that may be preventing clients from reaching their full potential. Consider the following points:
- The subtalar joint is pivotal to pivoting! It helps the body twist while the foot remains rooted on the ground (Moyer 2017).
- The subtalar joint is known as a “shock absorber” because “it determines the distribution of forces upon the skeleton and soft tissues of the foot” (Chaitow & DeLany 2011).
- Subtalar joint instability may lead to orthopedic problems that ultimately affect the knees, hips and lower back. When this joint is unstable, “the biomechanical effects can be tremendous” (Weil 2007).
- The interosseous talocalcaneal ligament is the subtalar joint’s main ligament, but there are four small ones as well: the anterior, posterior, lateral and medial talocalcaneal ligaments (Moyer 2017).
- Common foot and ankle problems associated with subtalar instability include posterior tibial tendinitis, anterior tibial tendinitis and plantar fasciitis (Weil 2007).
- Several tendons cross the subtalar joint to help balance the ankle during standing and walking, and their function depends on their relation to the subtalar joint axis (Krähenbühl et al. 2017).
- The subtalar joint is “a source of movement that can compensate for limitations in other structures” (Thompson 2001). Proper biomechanical assessment is therefore crucial when working with a client.