Which is an action of the peroneus brevis?

• A. Assist to plantar flex the ankle
• B. Dorsiflex the ankle
• C. Evert the foot
• D. Invert the foot

Answer: (A)

Peroneus brevis sits on the outside of the lower leg and helps move the foot away from the midline (eversion) while also contributing to pointing the toes downward (plantar flexion) at the ankle. While its main action is eversion, it can assist with plantar flexion, especially during activity when stability and propulsion are needed. Among the options, plantar flexion is a valid action this muscle can contribute to, making it a correct choice. Dorsiflexion and inversion are functions of other muscles (front-lower-leg muscles for dorsiflexion, medial-side muscles for inversion), so they don’t represent actions of the peroneus brevis as directly.