Muscles of Dorsum of Foot and Sole of Foot (four layers)

Question 1

Extensor Digitorum Brevis

Answer 1

O: ant. dorsal calcaneus, ant/med to lat. malleolus, inf. extensor retinaculum

I: lat. 3 tendons attach to tendons of ext. digitorum; longus to digits 2-4

A: extends toes 2-4 at MTP joint; helps ext. dig. longus

N: deep peroneal n. (L5, S1)

Question 2

Extensor Hallucis Brevis

Answer 2

O: ant. dorsal calcaneus, ant/med to lat. malleolus, inf. extensor retinaculum

I: med. tendon of 4 tendons to base of proximal phalanx of hallux

A: extends hallux at MTP joint; assists ext. hallucis longus

N: deep peroneal n. (L5, S1)

Question 3

Abductor Digiti Minimi

Answer 3

O: med/lat processes of tuber calcanei; plantar aponeurosis; intermuscular septum

I: lat. side of prox phalanx of 5th digit (little toe)

A: abducts and flexes 5th digit

N: lat. plantar nerve (S2, S3)

Question 4

Flexor Digitorum Brevis

Answer 4

O: med. tuber calcaneus, plantar aponeurosis, intermuscular septum

I: both sides of middle phalanx of lateral four digits

A: flexes lateral 4 digits

N: med. plantar n. (S1, S2)

Question 5

Abductor Hallucis

Answer 5

O: med. process of tuber calcaneus, flexor retinaculum, plantar aponeurosis

I: med. side of base of prox. phalanx of hallux

A: abducts and flexes hallux

N: med. plantar n (S1, S2)

Question 6

Quadratus Plantae

Answer 6

O: med. surface and lat. margin of plantar surface of calcaneus

I: posterolateral margin of tendon of flex. dig. longus

A: helps flex. digitorum longus in flexing lateral 4 digits

N: lat. plantar n. (S2, S3)

Question 7

Lumbricals

Answer 7

O: tendons of flexor digitorum longus

I: med. sides of bases of phalanges of lat. 4 digits; ext. expansions of tendons of ext. digitorum longus

A: flexes prox. phalanx of hallux

N: med. plantar n. (S2-S3); lat. plantar n. (S2-S3)

Question 8

Flexor Hallucis Brevis

Answer 8

O: plantar surfaces of cuboid and lateral cuneiform bones

I: both sides of base of prox. phalanx of hallux

A: flexes proximal phalanx of hallux

N: medial plantar n. (S1, S2)

Question 9

Adductor Hallucis

Answer 9

O: oblique head: bases of metatarsals 2-4; transverse head: plantar ligaments of MTP jts

I: tendons of both heads attach to lat. side of base of prox. phalanx of hallux

A: adducts hallux, maintains transverse arch

N: lateral plantar n. (S2, S3)

Question 10

Flexor Digiti Minimi Brevis

Answer 10

O: base of 5th metatarsal bone

I: base of prox. phalanx of 5th digit

A: flexes proximal phalanx of 5th digit

N: lateral plantar n. (S2, S3)

Question 11

Plantar Interossei

Answer 11

O: bases of medial sides of metatarsal 3-5

I: med. bases of prox phalanges of digits 3-5

A: adducts digits 3-5 and flexes MTP jt

N: lateral plantar n. (S2, S3)

Question 12

Dorsal Interossei

Answer 12

O: adjacent sides of metatarsal bones 1-5

I: 1st- medial side of prox. phalanx of 2nd digit; 2-4- lat. sides of digits 2-4

A: abducts digits (2-4) and MTP jts

N: lateral plantar n. (S2-S3)