Intrinsic foot muscles

Question 1

Answer 1

Extensor digitorum brevis

• O: dorsal surface of the calcaneus
• I: distal phalanges of toes 2-4 (via EDL and extensor expansion)
• A: extension of toes 2-4
• N: deep peroneal nerve L5, S1

Question 2

Answer 2

Extensor Hallucis brevis

• O: dorsal surface of calcaneus
• I: dorsal surface of the base of the proximal phalanx of great toe
• A: extends the MTP joint of the great toe
• N: deep peroneal nerve L5, S1

Question 3

Answer 3

Abductor Hallucis

• O: Calcaneal tuberosity & plantar surface of calcaneus
• I: medial side of the base of the proximal phalanx of the big toe
• A: abduction of big toe
• N: medial plantar nerve L5, S1

Question 4

Answer 4

Abductor digiti minimi

• O: Calcaneal tuberosity, flexor retinaculum & plantar aponeurosis
• I: base of proximal phalanx of little toe (lateral plantar side)
• A: abduction of the little toe
• N: lateral plantar nerve via tibial nerve S1, S2

Question 5

Answer 5

Flexor digitorum brevis

• O: calcaneal tuberosirty, and plantar aponeurosis
• I: base of the middle phalanx of 2-5 digits (splits @ insertion)
• A: flexes toes 2-5
• N medial plantar nerve via tibial nerve L5, S1

Question 6

Answer 6

Quadratus Plantae

• O: medial head: medial surface of calcaneus
  
  • ​lateral head: lateral border of the plantar surface of calcaneus
• I: lateral margin of the flexor digitorum longus tendon
• A: flexes digits 2-5
• N: lateral plantar nerve S1, S2

Question 7

Answer 7

Lumbricals x4

• O: 1st: medial side of the first flexor digitorum longus tendon to 2nd toe
  
  • ​2-4th: two heads between tendons of FDL
• I: base of proximal phalanges of toes 2-5 (medial side via dorsal expansion)
• A: flexion of toes2-5 @ MTP joint, & extension of toes 2-5 @ IP joints
• N: 1st: medial plantar nerve S1-S3
  
  • ​2-4th: lateral plantar nerve S1-S3

Question 8

Answer 8

Flexor Hallucis Brevis

• O: plantar surface of cuboid bone, adjacent part of the lateral cuneiform bone
• I: the base of the proximal phalanx of the great toe (medial and lateral sides)
• A: flexes the MTP joint of big toe
• N: medial plantar nerve S1, S2

Question 9

Answer 9

Flexor digit minimi

• O: base of the 5th metatarsal & distal tendon of peroneus longus
• I: base of proximal phalanx of little toe
• A: flexion of little toe
• N: lateral plantar nerve via tibial nerve S2, S3

Question 10

Answer 10

Adductor Hallucis

• O: Oblique head: bases of metatarsals 2-4 distal tendon of the peroneus longus
  
  • transverse head: deep transverss metatarsal ligament, and plantar ligaments at MTP joints
• I: lateral side of the base of the proximal phalanx of the great toe
• A: adducts the big toe
• N: lateral plantar S1, S2

Question 11

Answer 11

Plantar interossei x3

• O: medial aspect of 3-5 metatarsal bones (each muscle has a single head)
• I: medial sides of the bases of proximal phalanges of the same digit
• A: adduction of toes 3-5 @ MTP joint
• N: lateral plantar nerve S2, S3

Question 12

Answer 12

Dorsal interossei x4

• O: each by 2 heads from adjacent side of the metatarsal bones
• I: side of the proximal phalanx and capsule of the MTP joint;
  
  • 1st- to the medial side of the 2nd digit
  • 2nd - 4th – to the lateral sides of the 2nd through 4th digits
• A: abduction of toes 2-4 @ MTP joint
• N: lateral plantar nerve S2, S3