Leg And Foot Muscles

Question 0

Extensor hallucis longus Origin? Insertion? Innervation? Action?

Answer 0

O: Middle part of anterior surface of fibula and interosseous membrane

I: Dorsal aspect of base of distal phalanx of great toe (hallux)

Inner: Deep fibular nerve (L5-S1)

Action: Extends great toe; dorsiflexes ankle

Question 1

Tibialis anterior Origin? Insertion? Innervation? Action?

Answer 1

O: Lateral condyle and superior half of lateral surface of tibia and interosseous membrane

I: Medial and inferior surfaces of medial cuneiform and base of 1st metatarsal

Inner: Deep fibular nerve (L4-L5)

Action: Dorsiflexes ankle; inverts foot; supports medial longitudinal arch of foot

Question 2

Extensor digitorum longus Origin? Insertion? Innervation? Action?

Answer 2

O: Lateral condyle of tibia and superior three fourths of anterior surface of interosseous membrane

I: Middle and distal phalanges of lateral four digits

Inner: Deep fibular nerve (L5-S1)

Action: Extends lateral four digits; dorsiflexes ankle

Question 3

Fibularis tertius Origin? Insertion? Innervation? Action?

Answer 3

O: Inferior third of anterior surface of fibula and interosseous membrane

I: Dorsum of base of 5th metatarsal

Inner: Deep fibular nerve (L5-S1)

Action: Dorsiflexes ankle; aids in eversion of foot

Question 4

Fibularis longus Origin? Insertion? Innervation? Action?

Answer 4

O: Head and superior two thirds of lateral surface of fibula

I: Base of 1st metatarsal and medial cuneiform

Inner: Superficial fibular nerve (L5-S2)

Action: Evert foot; weakly plantarflex ankle. FL supports transverse arch of foot

Question 5

Fibularis brevis Origin? Insertion? Innervation? Action?

Answer 5

O: Inferior two thirds of lateral surface of fibula

I: Dorsal surface of tuberosity of base of 5th metatarsal

Inner: Superficial fibular nerve (L5-S2)

Action: ????

Question 6

Gastrocnemius Origin? Insertion? Innervation? Action?

Answer 6

O: Lateral head-> Lateral aspect of lateral condyle of femur
Medial head-> Popliteal surface of femur, superior to medial condyle

I: Posterior surface of calcaneus via calcaneal tendon

Inner: Tibial nerve (S1 and S2)

Action: Plantarflexes ankle when knee is extended; raises heel during walking and flexes leg and knee joint

Question 7

Soleus Origin? Insertion? Innervation? Action?

Answer 7

O: Posterior aspect of head of fibula, superior quarter of posterior surface of fibula, soleal line, and medial border of tibia

I: Posterior surface of calcaneus via calcaneal tendon

Inner: Tibial nerve (S1 and S2)

Action: Plantarflexes ankle; steadies leg on foot

Question 8

Plantaris Origin? Insertion? Innervation? Action?

Answer 8

O: Inferior end of lateral supracondylar line of femur and oblique popliteal ligament

I: Posterior surface of calcaneus via calcaneal tendon

Inner: Tibial nerve (S1 and S2)

Action: Weakly assists gastrocnemius in plantarflexing ankle

Question 9

Flexor hallucis longus Origin? Insertion? Innervation? Action?

Answer 9

O: Inferior two thirds of posterior surface of fibula and inferior part of interosseous membrane

I: Base of distal phalanx of great toe

Inner: Tibial nerve (S2-S3)

Action: Flexes great toe at all joints; weakly plantarflexes ankle; supports medial longitudinal arch of foot

Question 10

Flexor digitorum longus Origin? Insertion? Innervation? Action?

Answer 10

O: Medial part of posterior surface of tibia inferior to soleal line and by a broad tendon to fibula

I: Bases of distal phalanges of lateral four digits

Inner: Tibial nerve (S2-S3)

Action: Flexes lateral four digits; Plantarflexes ankle; supports longitudinal arches of foot

Question 11

Tibialis posterior Origin? Insertion? Innervation? Action?

Answer 11

O: Interosseous membrane, posterior surface of tibia inferior to soleal line and posterior surface of fibula

I: Primarily to tuberosity of navicular; also to cuneiforms, cuboid and bases of 2-4th metatarsals

Inner: Tibial nerve (L4-L5)

Action: Plantarflexes ankle; inverts foot; supports medial longitudinal arch of foot

Question 12

Abductor hallucis Origin? Insertion? Innervation? Action?

Answer 12

O: Medial tubercle of tuberosity of calcaneus, flexor retinaculum, and plantar aponeurosis

I: Medial side of base of proximal phalanx of 1st digit

Inner: Medial plantar nerve (S2-S3)

Action: Abducts and flexes 1st digit

Question 13

Flexor digitorum brevis Origin? Insertion? Innervation? Action?

Answer 13

O: Medial tubercle of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa

I: Both sides of middle phalanges of lateral four digits

Inner: Medial plantar nerve (S2-S3)

Action: Flexes lateral four digits

Question 14

Abductor digiti minimi Origin? Insertion? Innervation? Action?

Answer 14

O: Medial and lateral tubercles of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa

I: Lateral side of base of proximal phalanx of 5th digit

Inner: Lateral plantar nerve (S2-S3)

Action: Abducts and flexes 5th digit

Question 15

Quadratus plantae Origin? Insertion? Innervation? Action?

Answer 15

O: Medial surface and lateral margin of plantar surface of calcaneus

I: Posterolateral margin of tendon of flexor digitorum longus

Inner: Lateral plantar nerve (S2-S3)

Action: Assists flexor digitorum longus in flexing lateral four digits

Question 16

Lumbricals Origin? Insertion? Innervation? Action?

Answer 16

O: Tendons of flexor digitorum longus

I: Medial aspect of expansion over lateral four digits

Inner: Medial one-> medial plantar nerve (S2-S3)
Lateral three-> lateral plantar nerve (S2-S3)

Action: Flex proximal phalanges; extend middle and distal phalanges of lateral four digits

Question 17

Flexor hallucis brevis Origin? Insertion? Innervation? Action?

Answer 17

O: Plantar surfaces of cuboid and lateral cuneiform

I: Both sides of base of proximal phalanx of 1st digit

Inner: Medial plantar nerve (S2-S3)

Action: Flexes proximal phalanx of 1st digit

Question 18

Adductor hallucis Origin? Insertion? Innervation? Action?

Answer 18

O: Oblique head-> Bases of metatarsals 2-4
Transverse head-> plantar ligaments of 3-5th metatarsophalangeal joints

I: Tendons of both heads attach to lateral side of base of proximal phalanx of 1st digit

Inner: Deep branch of lateral plantar nerve (S2-S3)

Action: Adducts 1st digit; assists in maintaining transverse arch of foot

Question 19

Flexor digiti minimi brevis Origin? Insertion? Innervation? Action?

Answer 19

O: Base of 5th metatarsal

I: Base of proximal phalanx of 5th digit

Inner: Superficial branch of lateral plantar nerve (S2-S3)

Action: Flexes proximal phalanx of 5th digit, thereby assisting with its flexion

Question 20

Plantar interossei (3) Origin? Insertion? Innervation? Action?

Answer 20

O: Bases and medial sides of metatarsals 3-5

I: Medial sides of bases of proximal phalanges of 3-5th digits

Inner: Lateral plantar nerve (S2-S3)

Action: Adduct digits 3-5 and flex metatarsophalangeal joints

Question 21

Dorsal interossei (4) Origin? Insertion? Innervation? Action?

Answer 21

O: Adjacent sides of metatarsals 1-5

I: First-> medial side of proximal phalanx of 2nd digit
Second-Fourth-> lateral sides of 2-4th digits

Inner: Lateral plantar nerve (S2-S3)

Action: Abduct digits 2-4 and flex metatarsophalangeal joints