Intrinsic Foot Muscles

Question 1

Abductor hallucis

Answer 1

O: medial tubercle of tuberosity of calcaneus, flexor retinaculum, and plantar aponeurosis
I: medial aspect of base of proximal phalanx of 1st digit
I: medial plantar nerve (S1-S2)
A: abducts and flexes great toe at metacarpophalangeal joint

Question 2

Flexor digitorum brevis

Answer 2

O: medial tubercle of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa
I: both sides of middle phalanges of lateral four digits
I: medial plantar nerve (S1-S2)
A: flexes lateral four digits at interphalangeal joint

Question 3

Abductor digiti minimi

Answer 3

O: medial and lateral tubercles of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa
I: lateral aspect of base of proximal phalanx of 5th digit
I: lateral plantar nerve (S1-S3)
A: abducts and flexes little toe

Question 4

Quadratus plantae

Answer 4

O: medial aspect and lateral margin of plantar surface of calcaneus
I: posterolateral margin of tendon of flexor digitorum longus
I: lateral plantar nerve (S1-S3)
A: assists flexor digitorum longus in flexing lateral four digits

Question 5

Lumbricals

Answer 5

O: tendons of flexor digitorum longus
I: medial aspect of expansion over lateral four digits
I: medial one- medial plantar nerve
lateral three- lateral plantar nerve (S2-S3)
A: flexes proximal phalanges and extend middle and distal phalanges of lateral four digits

Question 6

Flexor hallucis brevis

Answer 6

O: plantar surfaces of cuboid and lateral cuneiform
I: both sides of base of proximal phalanx of 1st digit
I: medial plantar nerve (S1-S2)
A: flexes great phalanx at great toe

Question 7

Adductor hallucis

Answer 7

O: oblique head- bases of metatarsals 2-4
transverse head- plantar ligaments of metatarsophalangeal joints
I: tendons of both heads attach to lateral side of base of proximal phalanx of first digit
I: deep branch of lateral plantar nerve (S2-S3)
A: adducts great toe; assists in maintaining transverse arch of foot

Question 8

Flexor digiti minimi brevis

Answer 8

O: base of 5th metatarsal
I: base of proximal phalanx of 5th digit
I: superficial branch of lateral plantar nerve (S2-S3)
A: flexes proximal phalanx of little toe, thereby assisting with its flexion

Question 9

Plantar interossei (3 muscles)

Answer 9

O: bases and medial sides of metatarsals 3-5
I: medial sides of bases of proximal phalanges of digits 3-5
I: lateral plantar nerve (S2-S3)
A: adducts digits (3-5) and flex metatarsophalangeal joints

Question 10

Dorsal interossei (4 muscles)

Answer 10

O: adjacent sides of metatarsals 1-5
I: first- medial side of proximal phalanx of 2nd digit
2nd-4th- lateral sides of digits 2-4
I: lateral plantar nerve (S2-S3)
A: abducts digits (2-4) and flex metatarsophalangeal joints