Tibialis anterior muscle

The tibialis anterior muscle arises from:

• the lateral condyle of the tibia.[1]
• the upper 2/3 of the lateral surface of the tibia.[2]
• the adjoining part of the interosseous membrane.
• the deep surface of the fascia.
• the intermuscular septum between it and the extensor digitorum longus.

The fibers of this circumpennate muscle are relatively parallel to the plane of insertion, ending in a tendon, apparent on the anteriomedial dorsal aspect of the foot close to the ankle.

It passes through the most medial compartments of the transverse and cruciate crural ligaments. It is inserted into the medial and under surface of the medial cuneiform bone and the base of the first metatarsal bone.[2]

The tibialis anterior muscle is the most medial muscle of the anterior compartment of the leg. It is responsible for dorsiflexing and inverting the foot, and is the largest dorsiflexor of the foot.[1] The muscle has two origins, one being the lateral tibial condyle and the other being the upper lateral surface of the tibia, and inserts on the medial surface of the medial cuneiform and adjoining part of base of the first metatarsal of the foot allowing the toe to be pulled up and held in a locked position. It also allows for the ankle to be inverted giving the ankle horizontal movement allowing for some cushion if the ankle were to be rolled. It is innervated by the deep peroneal nerve and acts as both an antagonist and a synergist of the tibialis posterior. However, the most accurate antagonist of the tibialis anterior is the peroneus longus. The tibialis anterior aides in the activities of walking, running, hiking, kicking a ball, or any activity that requires moving the leg or keeping the leg vertical. It functions to stabilize the ankle as the foot hits the ground during the contact phase of walking (eccentric contraction) and acts later to pull the foot clear of the ground during the swing phase (concentric contraction). It also functions to 'lock' the ankle, as in toe-kicking a ball, when held in an isometric contraction.[4]

Antagonists are plantar-flexors of the posterior compartment such as soleus and gastrocnemius.

The movements of tibialis anterior are dorsiflexion and inversion of the ankle. However, actions of tibialis anterior are dependent on whether the foot is weight bearing or not (closed or open kinetic chain). When the foot is on the ground, the muscle helps to balance the leg and talus on the other tarsal bones so that the leg is kept vertical even when walking on uneven ground.

Some clinicians attempt to treat tibialis anterior muscle issues with acupuncture techniques, such as dry needling.[1] There is significant bias in studies evaluating the efficacy of acupuncture versus medical treatments,[5] and the decision to use acupuncture should be made carefully.

A tibialis anterior hernia is a rare type of hernia in which fat or other material protrudes through a defect in the tibialis anterior muscle.[6] It may be caused by trauma, such as an inadvertent kick to the lower leg from an opposing player in a football match.

medial view of dissected ankle has two muscles

• 
  Lateral aspect of right leg.
• 
  Tibialis anterior muscle
• 
  Cross-section through top third and second third of right leg.
• 
  Tibialis anterior muscle
• 
  Ankle joint. Deep dissection. Lateral view *This has some structures labelled incorrectly e.g. tibialis anterior, extensor hallucis longus and cuboid bone

• Tibialis posterior muscle

This article incorporates text in the public domain from page 480 of the 20th edition of Gray's Anatomy (1918)

Wikimedia Commons has media related to Tibialis anterior muscles.

• Anatomy photo:15:st-0415 at the SUNY Downstate Medical Center
• Tibialis Anterior from Wheeless' Textbook of Orthopaedics