Lower leg and foot: Extrinsic muscles (Anterior compartment)

Question 1

What are the 4 dorsiflexor muscles of the lower leg and foot?

Answer 1

Extensor hallucis longus
Extensor digitorum longus
Tibialis anterior
Peroneus/fibularis tertius

Question 2

All anterior muscles are..?

Answer 2

Dorsiflexors

Question 3

What is the function, origin, insertion and innervation of the extensor hallucis longus muscle?

Answer 3

Function – Extends great toe; dorsiflexes foot at ankle joint
Origin – Medial surface of fibula and adjacent interosseous membrane of leg
Insertion – Dorsal aspect of base of distal phalanx of great toe
Innervation – Deep fibular nerve (L5)

Question 4

What is the function, origin, insertion and innervation of the extensor digitorum longus muscle?

Answer 4

Function – Extends 2nd, 3rd, 4th and little toes; dorsiflexes foot at ankle joint
Origin – Lateral condyle of tibia, proximal three quarters of fibula and adjacent interosseous membrane of leg
Insertion – Dorsal aspects of bases of both the middle and distal phalanges of the 2nd, 3rd, 4th and little toes
Innervation – Deep fibular nerves (L5-S1)

Question 5

What is the function, origin, insertion and innervation of the tibialis anterior muscle?

Answer 5

Function – Dorsiflexes foot at ankle joint; inverts foot at subtalar and transverse tarsal joints
Origin – Lateral condyle and proximal half of lateral surface of tibia, adjacent interosseous membrane of leg
Insertion – Inferomedial aspect of medial cuneiform bone and base of first metatarsal bone
Innervation – Deep fibular nerves (L4-L5)

Question 6

What is the function, origin, insertion and innervation of the peroneus/fibularis tertius muscle?

Answer 6

Function – Dorsiflexes foot at ankle joint; assists in eversion of foot at subtalar and transverse tarsal joints
Origin – Medial surface of fibula and adjacent interosseous membrane of leg
Insertion – Dorsal aspect of base and body of fifth metatarsal bone
Innervation – Deep fibular nerves (L5-S1)