L22_The Intrinsic Foot

Question 1

Muscles of the dorsum of the foot

Describe Extensor hallucis brevis (origin, insertion, function, innervation)

Answer 1

Origin: Superolateral calcaneus

Insertion: Dorsal base of the proximal phalanx of hallux

Function: Extends hallux

Innervation: deep fibular nerve (L5-S1)

Question 2

Muscles of the dorsum of the foot

Describe Extensor digitorum brevis (origin, insertion, function, innervation)

Answer 2

Origin: Superolateral calcaneus

Insertion: extensor expansion of toes II-IV

Function: extends toes

Innervation: deep fibular nerve (L5,S1)

Question 3

Muscles of the first layer of the plantar surface of the foot

Describe Flexor digitorum Brevis (origin, insertion, function, innervation)

Answer 3

Origin: medial process of calcaneal tuberosity

Insertion: Middle phalanx of lateral 4 toes

Function: flexes toes

Innervation: medial plantar nerve (S2,S3)

Question 4

Muscles of the first layer of the plantar surface of the foot

Describe Abductor Hallucis (origin, insertion, function, innervation)

Answer 4

Origin: medial process of calcaneal tuberosity

Insertion: medial base of proximal phalanx of hallux

Function: flexes and abducts hallux

Innervation: medial plantar nerve (S2,S3)

Question 5

Muscles of the first layer of the plantar surface of the foot

Describe Abductor Digit Minimi (origin, insertion, function, innervation)

Answer 5

Origin: lateral and medial processes of calcaneal tuberosity

Insertion: Proximal phalanx of 5th toe (lateral side)

Function: abducts and flexes the PIP of 5th toe

Innervation: Lateral plantar nerve (S2,S3)

Question 6

Muscles of the second layer of the plantar surface of the foot

Describe Quadratus Plantae (origin, insertion, function, innervation)

Answer 6

Origin: medial and lateral calcaneus: Calcaneal tuberosity

Insertion: lateral border of the long flexor tendons

Function: offsets oblique pull of flexor digitorum longus to flex the toes

Innervation: lateral plantar nerve (S2,S3)

Question 7

Muscles of the second layer of the plantar surface of the foot

Describe Lumbricals (origin, insertion, function, innervation)

Answer 7

Origin: originate from the long flexor tendons

Insertion: Proximal phalanx and extensor expansion of toe II-V

Function: flexion of MTP, extension of IP joints

Innervation: 1st -> medial plantar nerve (S2,S3)

2nd,3rd,4th -> lateral plantar nerve (S2,S3)

Question 8

Muscles of the third layer of the plantar surface of the foot

Describe Flexor hallucis brevis medial and lateral head (origin, insertion, function, innervation)

Answer 8

Origin: cuboid, lateral cuneiform, medial 1st metatarsal, long plantar ligament

Insertion: medial and lateral side of the proximal phalanx of hallux

Function: flexes the MTP joint of hallux

Innervation: medial plantar nerve (S2,S3)

Question 9

Muscles of the third layer of the plantar surface of the foot

Describe Adductor hallucis (origin, insertion, function, innervation)

Answer 9

Origin:

Oblique head -> bases of metatarsals II-IV

Transverse head -> MTP joints of digits II-V

Insertion: Lateral side of the base of the proximal phalanx of hallux

Function: adducts hallux, helps maintain the transverse arch of the foot

Innervation: lateral plantar nerve (S2,S3)

Question 10

Muscles of the third layer of the plantar surface of the foot

Describe Flexor Digiti Minimi Brevis (origin, insertion, function, innervation)

Answer 10

Origin: Base of 5th metatarsal, long plantar ligament

Insertion: Lateral base of the proximal phalanx of toe V

function: Flexes the MTP joint of toe V

Innervation: Lateral plantar nerve (S2,S3)

Question 11

Muscles of the fourth layer of the plantar surface of the foot

Describe Plantar interossei (origin, insertion, function, innervation)

Answer 11

Origin: medial base of metatarsals III-V

Insertion: Medial base of proximal phalanges and extensor expansion of digits III-V

Function: adducts digits III-V, flexes MTP and extend IP joints of digits III-V

Innervation: lateral plantar nerve (S2,S3)

Question 12

Muscles of the fourth layer of the plantar surface of the foot

Describe Dorsal interossei (origin, insertion, function, innervation)

Answer 12

Origin: Adjacent sides of metatarsals I-V

Insertion: 1st and 2nd on either side, the base of the 1st phalanx of digit II, 3rd and 4th on the lateral side of the proximal phalanx of toes III and IV

Function: abducts the toes, flexes MTP joints

Innervation: lateral plantar nerve (S2,S3)

Question 13

Explain the trajectory of the arteries to the dorsum of the foot

Answer 13

anterior tibial artery splits into

• dorsalis pedis: creates the arcuate arch and gives off a branch called the deep plantar artery that goes to the plantar of the foot
• lateral tarsal artery

From the arcuate arch -> dorsal metatarsal arteries and dorsal digital arteris

Question 14

Explain the trajectory of the arteries in the plantar of the foot

Answer 14

THE NEUROVASCULAR STRUCTURES TRAVEL IN THE 2ND LAYER OF THE FOOT

posterior tibial artery gives off 2 branches:

• lateral plantar artery : creates the plantar arch
• medial plantar artery

The deep plantar artery (dorsum of the foot) joins the plantar arch on the sole of the foot

From the plantar arch -> plantar metatarsal arteries and plantar digital arteries

Question 15

Tell me the myotomes of the lower limb

Answer 15