Muscles of Foot

Question 0

flexor hallucis longus

Answer 0

Origin: inferior 2/3s of posterior surface of fibula and inferior part of interosseous membrane
Insertion: base of distal phalanx of great toe (hallux)
Innervation: tibial nerve (S2, S3)
Action: flexes great toe at all joints; weakly plantar flexes ankle; supports medial longitudinal arch

Question 1

flexor digitorum longus

Answer 1

Origin: medial part of posterior surface of tibia inferior to soleal line and by a broad tendon to fibula
Insertion: bases of distal phalanges of lateral 4 digits
Innervation: tibial nerve (S2, S3)
Action: flexes lateral 4 digits; plantarflexes ankle; supports longitudinal arches of foot

Question 2

tibialis posterior

Answer 2

Origin: interosseous membrane; posterior surface of tibia inferior to soleal line; posterior surface of fibula
Insertion: primarily to tuberosity of navicular; cuneiforms; cuboid; bases of 2nd-4th metatarsals
Innervation: tibial nerve (L4, L5)
Action: plantar flexes ankle; inverts foot; supports medial longitudinal arch of foot

Question 3

abductor hallucis

Answer 3

Origin: medial tubercle of tuberosity of calcaneus; flexor retinaculum; plantar aponeurosis
Insertion: medial side of base of proximal phalanx of 1st digit
Innervation: medial plantar nerve (S2, S3)
Action: abducts and flexes 1st digit

Question 4

flexor digitorum brevis

Answer 4

Origin: medial tubercle of tuberosity of calcaneus, plantar aponeurosis, and intermuscular septa
Insertion: both sides of middle phalanges of lateral 4 digits
Innervation: medial plantar nerve (S2, S3)
Action: flexes lateral 4 digits

Question 5

abductor digiti minimi

Answer 5

Origin: medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa
Insertion: lateral side of base of proximal phalanx of 5th digit
Innervation: lateral plantar nerve (S2, S3)
Action: abducts and flexes 5th digit

Question 6

quadratus plantae

Answer 6

Origin: medial surface and lateral margin of plantar surface of calcaneus
Insertion: posterolateral margin of tendon of flexor digitorum longus
Innervation: lateral plantar nerve (S2, S3)
Action: assists flexor digitorum longus in flexing lateral 4 digits

Question 7

lumbricals

Answer 7

Origin: tendons of flexor digitorum longus
Insertion: medial aspect of expansion over lateral 4 digits
Innervation: medial 1: medial plantar nerve (S2, S3)
lateral 3: lateral plantar nerve (S2, S3)
Action: flex proximal; extend middle and distal phalanges of lateral 4 digits

Question 8

flexor hallucis brevis

Answer 8

Origin: plantar surface of cuboid and lateral cuneiform
Insertion: both sides of base of proximal phalanx of 1st digit
Innervation: medial plantar nerve (S2, S3)
Action: flexes proximal phalanx of 1st digit

Question 9

flexor digiti minimi brevis (WHY)

Answer 9

Origin: base of 5th metatarsal
Insertion: base of proximal phalanx of 5th digit
Innervation: superficial branch of lateral plantar nerve (S2, S3)
Action: flexes proximal phalanx of 5th digit (assisting with its flexion)

Question 10

adductor hallucis

Answer 10

Origin: oblique head: bases of metatarsals 2-4
transverse head: plantar ligaments of 3rd-5th metatarsophalangeal joints
Insertion: tendons of both heads attach to lateral side of base of proximal phalanx of 1st digit
Innervation: deep branch of lateral plantar nerve (S2, S3)
Action: adducts 1st digit; assists in maintaining transverse arch

Question 11

dorsal interossei

Answer 11

Origin: adjacent sides of metatarsals 1-5
Insertion: first: medial side of bases of proximal phalanx of 2nd digit
Second-fourth: lateral sides of 2nd-4th digits
Innervation: lateral plantar nerve (S2, S3)
Action: abduct digits (2-4) and flex metatarsophalangeal joints

Question 12

plantar interossei

Answer 12

Origin: bases of medial sides of metatarsals 3-5
Insertion: medial sides of bases of proximal phalanges of 3rd-5th digits
Innervation: lateral plantar nerve (S2, S3)
Action: adduct digits (3-5) and flex metatarsophalangeal joints