Intrinsic Foot Muscles

Question 1

What’s the (only) intrinsic foot muscle in the dorsum of the foot?

Answer 1

extensor digitorum brevis (we’re considering ext. hallucis brevis to be part of ext. dig. brev.)

Question 2

What are the attachment pionts of extensor digitorum brevis?

Answer 2

S/P: anterior dorsal surface of the calcaneus

I/D: medial distal 4 phalanges (we’re considering ext. hallucis brevis to be part of ext. dig. brev.)

Question 3

What’s the action of extensor digitorum brevis?

Answer 3

Extension of the medial 4 toes

Question 4

How are abduction and adduction referenced when considering the foot?

Answer 4

Everything moving away/toward the 2nd toe (abd away; add toward)

Question 5

How many muscular layers are there in the sole of the foot?

Answer 5

4

Question 6

What are the muscles of the first layer in the sole of the foot?

Answer 6

• abductor hallucis
• flexor digitorum brevis
• abductor digiti minimi

Question 7

What’s the action of abductor hallucis?

Answer 7

abduction of the 1st toe

Question 8

What’s the action of flexor digitorum brevis?

Answer 8

flexion of 2nd-5th toes

Question 9

What’s the action of abductor digiti minimi

Answer 9

abduction of the 5th toe

Question 10

What are the muscles of the 2nd layer of the sole of the foot?

Answer 10

• quadratus plantae

- lumbricals

Question 11

What’s the action of quadratus plantae

Answer 11

assists flexor digitorum longus in flexion of the lateral 4 digits

Question 12

What are the tendons of the 2nd layer of the sole of the foot?

Answer 12

tendons of flexor hallucis longus and and flexor digitorum longus

Question 13

What are the muscles of the 3rd layer of the sole of the foot?

Answer 13

• flexor hallucis brevis
• adductor hallucis
• flexor digiti minimi brevis

Question 14

What’s the action of flexor hallucis brevis?

Answer 14

flexion of the 1st MTP joint

Question 15

What’s the action of adductor hallucis and what does it help maintain?

Answer 15

• adducts 1st toe

- helps maintain transverse arch

Question 16

What’s the action of flexor digiti minimi brevis?

Answer 16

flexion of the 5th MTP joint

Question 17

What are the muscles of the fourth layer of the sole of the foot?

Answer 17

• dorsal interossei

- plantar interossei

Question 18

What’s the action of dorsal interossei?

Answer 18

abduction of the 2nd-4th MTP joints (dorsal abduction)

Question 19

What’s the action of plantar interossei

Answer 19

adduction of the 3rd-5th MTP joints (plantar adduction)

Question 20

There are two sesamoid bones near the 1st phalanx of the foot. What muscle’s tendons adhere to these bones and what is the benefit served by the bones in these tendons?

Answer 20

• flexor hallucis brevis

- bones protect the tendons from pressure during standing and walking