Tibialis anterior: origin, insertion, action and innervation

The tibialis anterior is the muscle you feel right next to the sharp edge of the shin bone. It's the main muscle that lifts the front of the foot.

Where it is

It lies in the anterior compartment of the leg, just lateral to the anterior border of the tibia. Its tendon crosses the front of the ankle, where it stands out on the inner side when you pull your foot up, and continues to the inside of the foot.

Origin and insertion

• Origin: the lateral condyle and the upper half of the lateral surface of the tibia, and the interosseous membrane between the tibia and fibula.
• Insertion: the medial and inferior surfaces of the medial cuneiform and the base of the first metatarsal.

What it does

1. Dorsiflexion of the ankle: lifts the foot so the toes clear the ground when you swing the leg forward in walking.
2. Inversion of the foot: turns the sole inward.
3. Helps support the medial longitudinal arch of the foot.

When it's weak, the foot can't be lifted properly and drops while walking, a sign called foot drop.

Innervation and blood supply

The deep fibular (peroneal) nerve (L4–L5) supplies it, and the anterior tibial artery, which runs alongside it, provides its blood.

How to remember it

• Tibialis anterior: in front, lifts the front of the foot.
• Tibialis anterior and tibialis posterior both insert on the medial side of the foot and both invert it.
• Front of the leg = deep fibular nerve.

Frequently asked questions

What does the tibialis anterior do?

It dorsiflexes the ankle and inverts the foot.

Where does the tibialis anterior insert?

On the medial cuneiform and the base of the first metatarsal.

Which nerve supplies the tibialis anterior?

The deep fibular (peroneal) nerve, from L4 and L5.

Sources

• OpenStax, Anatomy and Physiology 2e, 11.6 Appendicular muscles of the pelvic girdle and lower limbs
• Z-Anatomy, the libre 3D atlas of anatomy