Muscles - Leg (Anterior Compartment) Flashcards
Extensor digitorum longus
Lies lateral and deep to the TA. The EDL can be palpated on the dorsal surface of the foot.
Origin - lateral condyle of tibia and medial surface of fibula
Insertion - Fibers converge into a tendon that enters the dorsum of the foot. The tendon then splits into four pieces, each inserting onto a toe.
Innervation - Deep fibular nerve
Actions - Extensions of 4 lateral toes and dorsiflexion of the foot.
What are these muscles innervated by?
Deep fibular nerve (L4-S1).
Tibialis Anterior
It is the strongest dorsiflexor of the foot. To test the power of this muscle, patients could be asked to stand on their heels.
Origin - lateral surface of tibia
Insertion - medial cuneiform and base of metatarsal I
Innervation - Deep fibular nerve
Actions - dorsiflexion and inversion
Extensor hallucis longus
Located deep to the TA and EDL.
Origin - medial surface of the fibular shaft
Insertion - tendon crosses anterior to the ankle joint and attaches to the base of the distal phalanx of the great toe.
Innervation - deep fibular nerve
Actions - dorsiflexion of big toe and dorsiflexion of the foot.
What are the four muscles of the anterior compartment?
1) Tibialis anterior
2) Extensor digitorum longus
3) Extensor hallucis longus
4) Fibularis tertius
What is the blood supply of these muscles?
Anterior tibial artery.
What are the functions of these muscles?
What the borders of the anterior compartment?
Dorsiflex and invert.
Anteriorly - deep fascia and skin of leg
Posteriorly - interosseous membrane
Medially - lateral surface of tibia
Laterally - anterior intermuscular septum and medial surface of fibula.
Fibularis tertius
The fibularis tertius arises from the most inferior part of the EDL - not present in all individuals.
Origin - with the EDL at the medial fibial surface
Insertion - descends with EDL to the dorsum of the foot, until it diverges and inserts onto metatarsal V.
Innervation - deep fibular nerve
Actions - Eversion and dorsiflexion of the foot.
