Muscles of the Lateral Leg Compartment and Charts




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Muscles of the Lateral Leg Compartment and Charts

 

leg_muscle chart-Image result for posterior leg muscles

The muscles of the lateral leg compartment includes:

  • Peroneus longus
  • Peroneus brevis

Helpful Hints:

peroneus longus – (perone = fibula; longus = long)
peroneus brevis – (brevis = short)

The peroneus group is often termed the ‘fibularis group.’ This group of muscles originates from the fibula. (the term ‘peron’ means fibula) These muscles function primarily to stabilize the ankle and to provide support to the lateral arch of the foot. As the names would imply this group consists of three muscles of unequal size.

The peroneus longus is the longest muscle of the group, followed by the shorter peroneus brevis, and finally the smallest of the group the peroneus tertius.

The peroneus tertius is not discussed in this particular section of the tutorial, because it resides in the anterior compartment of the lower leg. To review the peroneus tertius, as well as other muscles of the anterior leg compartment, please see the Muscles of the Anterior Leg Compartment.

For a discussion of ‘compartment syndrome‘ of the lower leg, please review the Biomechanical Considerations section of this tutorial.

Origin:

As the name would imply, the muscles of the peroneus group all originate from the fibula. It is interesting to note the way the points of insertion get progressively lower on the fibula.

Peroneus longus – This muscle originates from the fibular head and the proximal 2/3 shaft of the fibula.
Peroneus brevis – This muscle originates from the distal 2/3 shaft of the fibula.
Insertion:

Peroneus longus – This muscle inserts onto the inferior base of the first metatarsal and the first cuneiform. The peroneus longus tendon travels posterior, and then inferior, to the lateral malleolus, and then travels inferiorly to the tarsals to insert onto the proximal inferior base of metatarsal 1, and the inferior base of cuneiform 1. This muscle is on the lateral aspect of the tibia, yet inserts onto a structure on the medial aspect of the tibia by having an inserting tendon travel underneath the tarsals of the foot.

Peroneus brevis – This muscle inserts onto the tuberosity at the lateral base of the fifth metatarsal. The inserting tendon of this muscle follows the tendon of the peroneus longus posterior, and then inferior, to the lateral malleolus to then insert onto the proximal end of the fifth metatarsal.

Action:

The actions of this muscle group are extremely interesting to study. Although the peroneus brevis and the peroneus tertius share very similar origins and insertions, the actions are opposing to one another. This is due to the use of the lateral malleolus acting as a ‘pulley’ to redirect the line of force on the insertion point of the peroneus brevis.

Peroneus longus – The action of this muscle is ankle joint plantar flexion and subtalar joint eversion.
Peroneus brevis – The action of this muscle is ankle plantar flexion and subtalar eversion.

Charts and Posters:

Muscles-of-the-Posterior-Thigh-poster-anatomychart

download chart-Image result for posterior leg muscles

Image result for posterior leg muscles

 




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