Foot Muscles and Innervation

Question 1

Abductor Hollucis

Answer 1

part of 1st layer
lies on medial side of foot
O- Medial tubercle of tuberosity of calcaneus; flexor retinaculum; plantar aponeurosis
I- Medial side of base of proximal phalanx of 1st digit
A- ABD and flexion of great toe (hallux)
N- Medial Plantar nerve (S2,S3)

Question 2

Flexor Digitorum Brevis

Answer 2

part of 1st layer
lies immediately deep to plantar aponeurosis
O- Medial tubercle of tuberosity of calcaneus; plantar aponeurosis; inter muscular septa
I- Both sides of middle phalanges of lateral 4 digits
A- flexion of lateral 4 digits
N- Medial Plantar nerve (S2,S3)

Question 3

Abductor Digiti Minimi

Answer 3

part of 1st layer
O- Medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis; inter muscular septa
I- Lateral side of base of proximal phalanx of 5th digit
A- ABD and flexion of 5th digit (little toe)
N- Lateral plantar nerve (S2,S3)

Question 4

Quadratus Plantae

Answer 4

part of 2nd layer
realigns pull on FDL
O- Medial surface and lateral margin of plantar surface of calcaneus
I- Posterolateral margin tendon of FDL
A- Assists FDL in flexing lateral 4 digits
N- Lateral Plantar nerve (S2,S3)

Question 5

Lumbricals (1-4)

Answer 5

part of 2nd layer
O- Individual tendons of FDL
I- Medial aspect of expansion over lateral 4 digits
A- flexion of proximal phalanges; extends middle and distal phalanges lateral 4 digits
N- 1st lumbrical- medial plantar nerve (S2,S3)
2-4 lumbricals- Lateral plantar nerve (S2,S3)

Question 6

Flexor Hallucis Brevis

Answer 6

part of 3rd layer
lies on either side of FHL tendon
O- Plantar surface of cuboid, intermediate and lateral cuneiforms
I- Both sides base of proximal phalanx of 1st digit
A- Flexion of proximal phalanx of 1st digit
N- Medial plantar nerve (S2,S3)

Question 7

Adductor Hallucis

Answer 7

part of 3rd layer
has two head
looks like the number 7
O- oblique head- bases of metatarsals 2-4
transverse head - plantar ligaments of MTP joints
I- Lateral side base of the proximal phalanx of 1st digit
A- ADD of 1st digit; assist maintaining transverse arch by pulling lateral 4 digits medial
N- Lateral Plantar nerve (S2,S3)

Question 8

Flexor Digit Minimi Brevis

Answer 8

part of 3rd layer
O- Base of 5th metatarsal
I- Base of proximal phalanx of 5th digit
A- Flexion of proximal phalanx of 5th digit
N- Lateral Plantar Nerve (S2,S3)

Question 9

Plantar Interossei

Answer 9

part of 4th layer, numbered 1-4 medial to lateral
all these muscles are unipennate
O- Bases and medial sides of metatarsals 3-5
I- Medial sides of bases of phalanges of 3rd-5th digits
A- ADD digits 3-5; flex MP joints
N- Lateral plantar nerve (S2,S3)

Question 10

Dorsal Interossei

Answer 10

part of the 4th layer, number 1-4 medial to lateral
all these muscles are bipennate
O- Adjacent sides of metatarsals 1-5
I- 1st- medial side of proximal phalanx of 2 digit
2nd-4th- lateral side of 2nd-4th digits
A- ABD digits 2-4; flexes MP joints
N- Lateral plantar nerve (S2,S3)