The tibialis anterior action is to do what?

• A. Dorsiflex the ankle, invert the foot
• B. Invert the foot, dorsiflex the ankle
• C. Invert the foot, plantar flex the ankle
• D. Extend the knee, invert the foot

Answer: (A)

The tibialis anterior primarily acts at the ankle to lift the foot and turn the sole inward. Specifically, it dorsiflexes the ankle (raises the foot upward) and inverts the foot (turns the sole toward the midline). These two actions together describe what this muscle does most during common movements like walking, where clearing the toes requires dorsiflexion and stabilizing the foot often involves some inward turning.

Plantar flexion, pushing the foot downward, is mainly the job of the calf muscles, so that would not be correct here. Extending the knee isn’t a primary action of this muscle either, even though it crosses the knee, because its major effects are at the ankle and foot. That combination—dorsiflexion of the ankle and inversion of the foot—is exactly what the tibialis anterior does.