Dorsiflexors

Question 1

Common Features of anterior compartment

-tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius

Answer 1

Innervation- Deep Peroneal Nerve L5-S1 (tib ant L4-5)

Action- assist in DF of ankle

Question 2

Tibialis Anterior

Answer 2

Origin- upper 1/2 - 2/3 of lat surface of tibia, adjacent to IOM
Insertions- med surface of medial cuneiform and base of MT1
- blends with insert of peroneus longus

Actions- inversion of foot

Question 3

Extensor Digitorum Longus

Answer 3

Origins- upper 2/3 ant surface of fibula, upper part of IOM, lat tib condyle
Insertion- single tendon until ankle then splits to base of middle and distal phalanges of toes 2-5 into extensor hood (dorsal digital expansion)

Actions- extension of lat 4 toes at MTP joints
- extension at IP joints

Question 4

Extensor Hallucis Longus

-powerful DF

Answer 4

Origin- middle 1/2 of ant surface of fibula and adjacent to IOM
Insertions- dorsal surface, base of distal phalanx of great toe (possibility of slips to base of prox phalanx and MT1)

Action- extends all great toe joints

Question 5

Peroneus Tertius

-weak DF of foot with EDL

Answer 5

Origin- lower 1/4 of med fibula and adjacent IOM
Insertion- base of MT5, medial and dorsal aspect

Action- weak evertor of foot