LM 6.5: Foot

Question 1

what are the muscles on the dorsum of the foot?

Answer 1

1. extensor digitorum brevis

extends digits 2-5

2. extensor hallucis brevis

extends big toe

3. dorsal interossei muscles

they are deep to the extensor digitorum brevis and extensor hallucis longus

Question 2

what innervates the dorsal interossei muscles?

Answer 2

lateral plantar nerve

Question 3

what innervates the extensor digitorum brevis and extensor hallucis brevis?

Answer 3

deep fibular nerve

Question 4

what does the anterior tibial artery turn into and when?

Answer 4

the anterior tibial artery becomes the dorsalis pedis artery after passing by the malleolus

Question 5

what are the branches of the posterior tibial artery in the foot?

Answer 5

the lateral and medial plantar arteries

Question 6

what does the medial plantar nerve innervate?

Answer 6

1. abductor hallucis
2. flexor digitorum brevis
3. flexor hallucis brevis
4. 1st lumbrical

Question 7

what does the lateral plantar nerve innervate?

Answer 7

all other muscles of the sole of the foot and the dorsal interossei

so the only things it doesn’t innervate are the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and 1st lumbrical

Question 8

what does the deep fibular nerve innervate?

Answer 8

1. extensor digitorum brevis
2. extensor hallucis brevis

these are on the dorsum of the foot

Question 9

what is the function of the plantar aponeurosis?

Answer 9

it protects the deeper structures of the foot

it can become inflamed with repetitive high-impact and poor support = plantar fasciitis

Question 10

which muscles are in the first layer deep to the plantar aponeurosis?

Answer 10

1. flexor digitorum brevis
2. abductor hallucis
3. abductor digiti minimi

Question 11

which muscles are in the second layer deep to the plantar aponeurosis?

Answer 11

1. quadrates plantae
2. 4 lumbricals

flex MP joint and extend IP joints

Question 12

what is the attachment and action of the quadratus plantae muscle?

Answer 12

proximal attachment = calcaneus

distal attachment = tendons of the flexor digitorum longus

action = assists with flexion of digits 2-5

Question 13

what innervates the 4 lumbrical muscles of the foot?

Answer 13

1st lumbrical is innervated by the medial plantar nerve

2-4 are innervated by the lateral plantar nerve

Question 14

what is the action and innervation of the flexor hallucis brevis?

Answer 14

it has a medial and lateral head that you can see on either side of the tendon of the flexor hallucis longus that is superficial to it

the sesamoid bones are embedded in its two tendons

it flexes the big toe

it’s innervated by the medial plantar nerve

Question 15

what is the action and innervation of the adductor hallucis muscle?

Answer 15

there is an oblique and transverse head that helps to adduct the big toe

they’re innervated by the lateral plantar nerve

Question 16

which muscles are in the deepest layer of the foot?

Answer 16

there are 4 dorsal interossei muscles

Question 17

what is the action and innervation of the dorsal interossei muscles?

Answer 17

the abduct the MP joints of digits 2-4

they’re innervated by the lateral plantar nerve

Question 18

what is the innervation and action of the plantar interossei muscles of the foot?

Answer 18

they adduct the MP joints of digits 3-5

they are innervated by the lateral plantar nerve

Question 19

what is the function of the flexor retinaculum?

Answer 19

it holds the flexor tendons and tendon of tibias posterior as well as neuromuscular structures in place

it’s between the tibia and the calcaneus

Question 20

which muscles evert the foot?

Answer 20

1. fibularis longus
2. fibularis brevis
3. fibularis tertius