Muscles - Anterior Leg

Question 1

Describe the muscles of the anterior leg, including:

location
structure
function

Answer 1

Location:
anterior compartment of the leg. bordered by:
interosseous membrane, anterior septa and crural fascia; lateral tibia and medial fibula

Structure:
one layer containing 4 muscles:
Tibialis anterior
Extensor digitorum longus
extensor hallucis longus
fibularis tertius (not always present)

Function:
the primary function of these muscles is to dorsiflex the ankle and extend the toes. In addition the tibialis anterior inverts the foot, and the fibularis tertius assists in everting the foot.

Question 2

Describe the tibialis anterior muscle:

Answer 2

PA: lateral condyle of tibia and superior lateral surface of tibia
DA: base of medial cuneiform and 1st MT
NS: deep fibular
A: dorsiflexes ankle and inverts foot

Question 3

Describe the extensor digitorum longus muscle:

Answer 3

PA: lateral condyle of tibia, medial surface of fibula (superior three quarters) and adjacent interosseous membrane
DA: extensor expansion, and middle and distal phalanges digits 2-5
NS: deep fibular
A: extends digits 2-5, dorsiflexes ankle

Question 4

Describe the extensor hallucis longus muscle:

Answer 4

PA: anterior fibula (middle) and interosseous membrane
DA: base of distal phalanx digit 1 (dorsal surface)
NS: deep fibular
A: extends digit 1, dorsiflexes ankle

Question 5

Describe the fibularis tertius muscle:

Answer 5

PA: anterior fibula (inferior third) and adjacent interosseous membrane
DA: base of 5th MT
NS: deep fibular
A: dorsiflexes ankle, aids in eversion of the foot