What structure does the fibularis tertius primarily affect?

The fibularis tertius is a muscle located in the lower leg that plays a significant role in the movement of the foot and ankle. It primarily affects the ankle joint by assisting in dorsiflexion, which is the movement that brings the top of the foot toward the shin. In addition to aiding in dorsiflexion, the fibularis tertius also contributes to eversion of the foot, which involves turning the sole of the foot outward.

Understanding the location and function of the fibularis tertius is crucial for sports massage practitioners, as it helps identify how tightness or weakness in this muscle can lead to imbalances or issues in movement patterns, particularly in activities like running or jumping. The other joints mentioned, such as the knee, hip, and shoulder, are not directly affected by the fibularis tertius, which is distinctly positioned in the lower leg and directly influences the mechanics of the ankle.