Peroneus Tertius is a small, often overlooked muscle located in the lower leg, part of the anterior compartment, primarily responsible for dorsiflexion and eversion of the foot. It helps stabilize the ankle joint and plays a role in maneuvering the foot to adapt to varying terrains during walking and running. Functionally, it assists in pulling the toes upward and outward, contributing to a balanced gait.
The name "Peroneus Tertius" is derived from Latin, where "peroneus" relates to the fibula (the lateral bone of the leg), and "tertius" means "third," indicating its position relative to two other peroneal muscles.
Without the Peroneus Tertius, the ability to evert the foot effectively could be compromised, leading to decreased lateral stability of the ankle. This deficiency might result in a less efficient gait, making activities such as walking on uneven surfaces more challenging.
