Anterior Compartment

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Anterior compartment of the leg

    

       This compartment is also reffered to as the Extensors of the leg and foot

         -Tibialis anterior,

·        - Extensor hallucis longus,

·        - Extensor digitorum longus and

·        - Fibularis (peroneous) tertius

      The muscles contained within this compartment, which, as the name suggests, is located on the front portion of the leg. They are involved in extending the ankle joint and in the eversion and inversion of the foot. The anterior tibial artery and its venae comitantes provide the blood supply to this group of muscles.

       Innervation to these muscles is via the deep fibular (peroneal) nerve.

   

        Tibialis anterior

A:  Dorsiflexes the ankle and inverts foot.

O:  Lateral tibial condyle and upper anterolateral surface of the tibia.

I:    Base of 1st metatarsal and medial surface of medial cuneiform.

N: The most medial of the muscles in the anterior compartment of the leg.

      Extensor hallucis longus

A:   Powerful extensor of the toe, dorsiflexor of the foot and aids inversion of the foot.

O:  Anterior surface of the fibula and interosseous membrane.

I:    Base of distal phalanx of hallux.

 

    Extensor digitorum longus

A: Dorsiflexes the foot and extends the lateral four toes.

O: Lateral tibial condyle, anterior surface of the fibula and the lateral portion of the interosseous membrane.

I:  Muscle belly splits into 4 tendons, each forming an extensor expansion which further divides into 3 slips and insert onto the dorsum of the lateral four toes.

N: The middle slip inserts onto the base of the middle phalanx whilst the lateral slips pass on to the base of the distal phalanx.

 

     Fibularis tertius

A: Weak dorsiflexion of the ankle and eversion of the foot.

O: Distal quarter of the anterior surface of the fibula.

I:   Dorsal surface of the 5th metatarsal bone.

N: Rarely present in other primates and not always found in humans.

 

 

 

 

 


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