PT 692 Intrinsic Foot

Question 1

Abductor hallucis m.

Answer 1

Medial tubercle of calcaneal tuberosity; flexor retinaculum; plantar aponeurosis
Medial side of base of proximal phalanx of 1st digit
Medial plantar nerve
S2, S3
Abducts and flexes 1st digit
1st layer

Question 2

Flexor digitorum brevis m.

Answer 2

Medial tubercle of calcaneal tuberosity; plantar aponeurosis; intermuscular septa

Both sides of middle phalanges of lateral 4 digits

Medial plantar nerve
S2, S3

Flexes lateral 4 digits

1st layer

Question 3

abductor digiti minimi m.

Answer 3

Medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa

Lateral side of base of proximal phalanx of 5th digit

Lateral plantar nerve
S2, S3

Abducts and flexes little toe

1st layer

Question 4

Quadratus plantae m.

Answer 4

Medial surface and lateral margin of plantar surface of calcaneus

Posterolateral margin of tendon of flexor digitorum longus

Lateral plantar nerve
S2, S3

Assists flexor digitorum longus in flexing lateral 4 digits

2nd layer

Question 5

Lumbricals m.

Answer 5

Tendons of flexor digitorum longus

Medial aspect of expansion over lateral 4 digits

Medial one: medial plantar nerve
Lateral 3: lateral plantar nerve

S2, S3

flex proximal phalanges; extend middle and distal phalanges of lateral 4 digits.

2nd layer

Question 6

Flexor hallucis brevis m.

Answer 6

Plantar surfaces of cuboid and lateral cuneiforms

Both sides of base of proximal phalanx of 1st digit

Medial plantar nerve
S2, S3

Flexes proximal phalanx of 1st digit

3rd layer

Question 7

Adductor hallucis m.

Answer 7

Oblique head: bases of metatarsals 2-4
Transverse head: plantar ligaments of MTP joints

Lateral side of base of proximal phalanx of 1st digit

Deep branch of lateral plantar nerve
S2, S3

Traditionally said to adduct 1st digit; assists in transverse arch of foot by metatarsal medially

3rd layer

Question 8

Flexor digiti minimi brevis m.

Answer 8

Base of 5th metatarsal

Base of proximal phalanx of 5th digit

Superficial branch of lateral plantar nerve
S2, S3

Flexes proximal phalanx of 5th digit; thereby assisting with its flexion

3rd layer

Question 9

Plantar interossei m. (3 muscles)

Answer 9

Plantar aspect of medial sides of shafts of metatarsals 3-5

Medial sides of bases of proximal phalanges of 3rd-5th digits

Lateral plantar nerve
S2, S3

Adducts digits 3-5 and flex MTP joints

4th layer
PAD

Question 10

Dorsal interossei m. (4 muscles)

Answer 10

Adjacent sides of shafts of metatarsal 1-5

1st: medial side of proximal phalanx of 2nd digit
-2nd - 4th: lateral sdies of 2nd-4th digits

Lateral plantar nerve
S2, S3

Abducts digits 2-4 and flex MTP joints

4th layer
DAB

Question 11

Extensor digitorum brevis m.

Answer 11

Calcaneus (floor of tarsal sinus); interosseous talocalcaneal ligament; stem of inferior extensor retinaculum

Long extensor tendons of 4 medial digits (toes 2-4)

Deep fibular nerve
L5 or S1, or both

Aids the extensor digitorum longus in extending the 4 medial toes at the MTP and IP joints

Dorsum of the foot

Question 12

Extensor hallucis brevis m.

Answer 12

In common with extensor digitorum brevis

Dorsal aspect of base of proximal phalanx of great toe

Deep fibular nerve
L5 or S1, or both

Aids the extensor hallucis longus in extending the great toe at the MTP joint

Dorsum of the foot