Tibialis Anterior Muscle Anatomy

Location & Overview

The tibialis anterior muscle is also known as the tibialis anticus. It is a superficial muscle located lateral to the anterior body of the tibia. It is easily palpable and is the largest of the four muscles in the anterior compartment of the lower leg. The other three anterior compartment muscles are the extensor hallucis longus, extensor digitorum longus and the fibularis tertius ^{[1] [2]}.

Origin & Insertion

The tibialis anterior originates from the lateral condyle of the tibia, the proximal two-thirds of the lateral surface of the tibia, and the anterior side of the interosseous membrane (which is a membrane in between the tibia and fibula). It works its way inferiorly from this origin where it then passes the ankle joint and reaches the foot. On the foot, it then inserts on the medial cuneiform and the base of the first metatarsal. This tendinous insertion is the most medial tendon of the ankle and foot. This distal tendon is held against the front of the ankle and foot by the extensor retinaculum which covers the anterior aspect of the ankle and foot ^{[3] [4] [5]}.

The tibialis anterior has some individual variation of its tendinous insertion. The most common variant is the occurrence of one additional band and sometimes two ore more additional insertions have been observed. There are variations which have been observed with the locations of the attachment points for both the origin and insertion of this muscle. The most common origin and insertion though is listed in the above paragraph ^[6].

Actions

The primary function of the tibialis anterior muscle is to cause dorsiflexion of the foot. Dorsiflexion is when you lift the front your foot upwards towards the shin and by doing so bend the ankle joint. The tibialis anterior is the strongest dorsiflexor muscle of the foot. The tibialis anterior can also work together with the tibialis posterior to cause inversion of the foot. Inversion would be turning the sole of the foot to the side in a medial direction (the opposite of eversion). Furthermore, due to the tibialis anterior inserting onto the medial border of the foot, the tibialis anterior can also assist in maintaining the medial arch of the foot ^{[7] [8] [9] [10]}.

Innervation

The tibialis anterior muscle is innervated by the deep peroneal nerve (L4, L5, S1). The deep peroneal neve is also called the deep fibular nerve ^{[11] [12] [13] [14]}.

Blood Supply

Blood is supplied to the proximal area of the tibialis anterior via the anterior tibial artery. Blood is supplied to the distal tendon via the medial tarsal arteries, which are branch of the dorsalis pedis artery ^{[15] [16] [17] [18]} .