The tibialis posterior is a muscle that plays a foundational role in the mechanics of the lower limb. Understanding its location provides insight into the overall health and function of the foot and ankle. It is important for comprehending its contributions to movement, stability, and maintaining proper foot structure.
Anatomical Home of the Tibialis Posterior
The tibialis posterior muscle is situated deep within the posterior compartment of the lower leg, nestled between other muscles like the flexor digitorum longus and the flexor hallucis longus. It originates from the upper two-thirds of the posterior surfaces of both the tibia (shin bone) and the fibula, as well as the interosseous membrane that connects these two bones.
From its origin, the muscle’s tendon extends downward, wrapping behind the medial malleolus, the prominent bony bump on the inside of your ankle. After passing the ankle, the tendon inserts into multiple bones in the foot, primarily the navicular and medial cuneiform bones. It may also attach to the heel bone in some individuals.
Key Roles in Foot and Ankle Movement
The tibialis posterior muscle performs several actions that contribute to foot movement. It is primarily responsible for plantarflexion, which is pointing the foot downward at the ankle joint. This muscle also facilitates foot inversion, the movement that turns the sole of the foot inward.
Beyond these movements, the tibialis posterior supports the medial longitudinal arch of the foot. This support is evident during activities like walking and standing, helping distribute body weight and maintain foot integrity. Its actions contribute to overall foot stability and balance, assisting in resisting lateral sway, especially when balancing on one leg.
Understanding Common Issues
Problems associated with the tibialis posterior muscle manifest as conditions like tibialis posterior dysfunction (PTTD) or tendinopathy, which is an inflammation or degeneration of the tendon. PTTD is referred to as adult acquired flatfoot because it is a common cause of arch collapse that develops in adulthood.
These conditions can arise from factors including overuse from activities like running, walking, or climbing stairs. Trauma or previous ankle injuries can also contribute. Symptoms include pain, swelling, redness, and warmth along the inside of the foot and ankle, following the tendon’s path. As the condition progresses, individuals may notice a flattening of the foot’s arch and the heel tilting outward.
Finding Your Tibialis Posterior
Locating the tibialis posterior muscle directly can be challenging due to its deep position within the lower leg. However, its tendon is more accessible and can be felt.
To find it, first locate the medial malleolus, the prominent bony bump on the inside of your ankle. The tibialis posterior tendon passes just behind this bony landmark. To make the tendon more noticeable, gently invert your foot (turn the sole inward) or point your foot downward against a slight resistance while feeling the area directly behind the medial malleolus. This action will cause the tendon to tighten, allowing you to feel its presence.
This method is for general awareness and is not a substitute for a professional medical assessment.