Tibialis anterior muscle

Structure

The tibialis anterior muscle is the most medial muscle of the anterior compartment of the leg.

The muscle ends in a tendon which is apparent on the anteriomedial dorsal aspect of the foot close to the ankle. Its tendon is ensheathed in a synovial sheath. The tendon passes through the medial compartment superior and inferior extensor retinacula of the foot.****

Origin

The tibialis anterior muscle arises from the upper 2/3 of the lateral surface of the tibia and the adjoining part of the interosseous membrane and deep fascia overlying it,**** and the intermuscular septum between this muscle and the extensor digitorum longus.

Insertion

It is inserted into the medial and inferior surface of the medial cuneiform bone, and adjacent portion of the first metatarsal bone.'

Nerve supply

The tibialis anterior muscle is innervated by the deep fibular nerve, and recurrent genicular nerve (L4).

Variation

A deep portion of the muscle is rarely inserted into the talus, or a tendinous slip may pass to the head of the first metatarsal bone or the base of the first phalanx of the great toe.

The tibiofascialis anterior, a small muscle from the lower part of the tibia to the transverse or cruciate crural ligaments or deep fascia.

Actions/movements

The muscle acts to dorsiflex and invert the foot. It is the largest dorsiflexor of the foot. The muscle also contributes to deceleration.

Function

The muscle helps maintain the medial longitudinal arch of the foot.**** It draws up and holds the toe in a locked position. The tibialis anterior aids in 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.

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.

Clinical significance

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. It may be caused by trauma, such as an inadvertent kick to the lower leg from an opposing player in a football match.

Additional images

medial view of dissected ankle has two muscles File:Gray1240.png|Lateral aspect of right leg. File:Tibialis anterior 2.png|Tibialis anterior muscle File:Braus 1921 293.png|Cross-section through top third and second third of right leg. File:Slide9DDDD.JPG|Tibialis anterior muscle File:Slide2WIKI.JPG|Ankle joint. Deep dissection. Lateral view *This has some structures labelled incorrectly e.g. tibialis anterior, extensor hallucis longus and cuboid bone

References

References

1. Ma, Yun-tao. (2011-01-01). "CHAPTER 14 - General Principles of Treating Soft Tissue Dysfunction in Sports Injuries". Churchill Livingstone.
2. (2005-01-01). "Chapter 18 - Pain in the lower limb". Churchill Livingstone.
3. Sinnatamby, Chummy. (2011). "Last's Anatomy". Elsevier Australia.
4. (2022-04-08). "10 Incredible Tibialis Raise Benefits".
5. (2011-05-01). "Dynamic measurements of musculus tibialis anterior ligaments with different angles". Journal of Biomechanics.
6. (2016). "Tibialis anterior muscle hernia: rare but not uncommon". BMJ Case Reports.