The anterior leg compartment muscles Charts and Posters




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The anterior leg compartment muscles Charts and Posters

 

The anterior leg compartment muscles discussed in this section include:

  • Tibialis anterior
  • Extensor digitorum longus
  • Extensor hallucis longus
  • Peroneus tertius

Helpful Hints:

tibialis anterior – (tibial = tibia; anterior = ventral)
extensor digitorum longus – (extensor = extends; digit = phalange; longus = long)
extensor hallucis longus – (hallux = great toe)
peroneus tertius – (perone = fibula; tertius = third)

The muscles of the leg are smaller and more compact than those of the thigh, which makes the study of the leg slightly more complicated than the thigh region.

Therefore, most texts will separate the leg anatomy into ‘compartments,’ which is what we will do here as well. Since the leg muscles are somewhat smaller and less prominent than the thigh, it is less obvious which muscles are being observed. In cases such as this it is very important to know precise points of origin and insertion.

Keep in mind that the peroneus tertius is part of a group of muscles arising from the fibula, often called the peroneus group, or fibularis group. The peroneus tertius is discussed separate from the other two muscles of the peroneus group, because it resides in the anterior compartment of the lower leg.

For a discussion of ‘compartment syndrome’ and ‘shin-splints’ of the lower leg, please review the Biomechanical Considerations section of this tutorial.

Origin:

Tibialis Anterior – This muscle originates at the lateral iliotibial tract and proximal 2/3 of the tibial shaft.
Extensor digitorum longus – This muscle originates at the lateral condyle of the tibia and the anterior fibula.
Extensor hallucis longus – This muscle originates at the anterior surface of the fibula.
Peroneus tertius – This muscle originates from the distal 1/3 of the fibula.

Insertion:

Tibialis anterior – This muscle inserts onto the inferior surface of both the medial cuneiform and the medial metatarsal. In foot anatomy ‘medial’ also refers to those structures termed ‘first,’ as in the ‘first metatarsal.’ The terms first, second, third, etc. begin with the most medial structure.’)
Extensor digitorum longus – This muscle inserts onto the middle and distal phalanx of the four lesser toes.
Extensor hallucis longus – This muscle inserts onto the base of the distal phalanx
of the great toe (also known as the hallux).
Peroneus tertius – This muscle inserts onto the superior base of the fifth metatarsal.

Action:

Tibialis anterior – The action of this muscle includes ankle dorsiflexion, and subtalar inversion.
Extensor digitorum longus – The action of this muscle includes extension of the metatarsophalangeal and interphalangeal joints of the four lesser toes; ankle dorsiflexion, and subtalar eversion.
Extensor hallucis longus – The action of this muscle includes extension of the metatarsophalangeal joint and interphalangeal joint of the great toe; also ankle dorsiflexion, and subtalar inversion.
Peroneus tertius – The action of this muscle is ankle dorsiflexion, and subtalar eversion. (Note: No use of the lateral malleolus to redirect the line of force.




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