Muscles of the Foot.

Question 1

What is the innervation to the muscles of the foot?

Answer 1

Tibial nerve, from branches of the medial and lateral plantar nerves.

Question 2

Which muscles of the foot are the only ones to be innervated by medial plantar nerve?

Answer 2

Abductor hallucis
Flexor digitorum brevis
Flexor hallucis brevis
1st lumbricle

Question 3

Which muscles of the foot are not innervated by the tibial nerve?

Answer 3

Extensor digitorum brevis, extensor hallucis brevis which are extrinsic muscles of the anterior leg compartment
-> Innervated by the deep fibular nerve.

Question 4

What are the groups of foot muscles?

Answer 4

Extrinsic muscles of the foot which arises from the compartments of the leg for foot eversion, inversion, dorsiflexion and plantarflexion.

Intrinisic muscles of the foot which are contained only in the foot for fine motor movements of toe.

Question 5

What are the types of intrinsic foot muscles?

Answer 5

Dorsal group muscles and plantar group muscles.

Question 6

What are the dorsal intrinsic muscles of the foot?

Answer 6

On the dorsal aspect of the foot for extension.
Extensor hallucis brevis
Extensor digitorum brevis.

Extrinsic muscles would cause dorsiflexion.

Question 7

What is the course of the extensor digitorum brevis?

Answer 7

Arises from the calcaenus and inferior extensor retinaculum to insert onto the toe 2, 3 and 4 for toe extension, laterally to the slip of the extensor digitorum longus,

Question 8

What are the layers of the muscles of the plantar aspect?

Answer 8

Plantar aspect is responsible for:
Flexion of toes via intrinsic muscles which contains 4 layers.
Plantar flexion via extrinsic muscles.

Question 9

Which muscles are present in the 1st layer of the plantar aspect of the foot?

Answer 9

Abductor hallucis innervated by medial plantar nerve
Abductor digit minimi innervated by lateral plantar nerve
Flexor digitorum brevis innervated by medial plantar nerve

Question 10

Which muscles are present in the 2nd layer of the plantar aspect of the foot?

Answer 10

2 intrinsic muscles only
Quadratus plantae
Lumbricals

(Extrinsic muscles are the flexor digitorum longus and flexor hallucis longus)

Question 11

Which muscles are present in the 3rd layer of the plantar aspect of the foot?

Answer 11

3 muscles:
Flexor hallucis brevis
Flexor digit minimi brevis
Adductor hallucis (oblique and transverse head)

Question 12

Which muscles are present in the 4th layer of the plantar aspect of the foot?

Answer 12

Interossei muscles
Dorsal interossei muscles
Plantar interossei muscles

Question 13

What is the course of the flexor digitorum brevis?

Answer 13

Arises from the calcaenus to bifurcate and attach laterally to the toes and allows the flexor digitorum longus to attach. It is innervated by the medial plantar nerve.

Question 14

What is the course of the abductor hallucis?

Answer 14

Arises from the calcaenus and flexor retinaculum to attach to the base of the 1st phalange for flexion of the MCP joint for abduction and flexion of the 1st toe. It is innervated by the medial plantar nerve.

Question 15

What is the course of the abductor digit minimi?

Answer 15

Arises from the medial and lateral aspects of the calcaenus to attach to the base of the 5th toe for abduction and flexion of the toe.

Innervated by the lateral plantar nerve.

Question 16

What is the flexor digitorum longus?

Answer 16

Extrinsic muscle which arises from the posterior compartment of the leg and attached to the distal phalanges of toes 2-5 for flexion. It is innervated by the medial plantar nerve.

It has attachments for the lumbricles and quadratus plantae.

Question 17

What is the quadratus plantae?

Answer 17

Has two tendons which arises from the calcaenus to the tendon of the flexor digitorum longus for toe flexion.

Question 18

What is the lumbricles?

Answer 18

Bipennate muscles arising from the tendons flexor digitorum longus to attach to the extensor hoods of the toes for:
Flexion of MCP
Extension of IP joints of IP AND DIP

Question 19

What is the innervation of the 1st lumbrical?

Answer 19

Medial plantar nerve

Question 20

What is the innervation of the 2-4th lumbrical?

Answer 20

Lateral plantar nerve

Question 21

What is the flexor hallucis brevis?

Answer 21

Originates from the tendon of tibialis posterior and cuboid and lateral cuneiform bone to insert into the base of the proximal hallux for flexion at MCP. Innervated by medial plantar nerve.

Question 22

What is the adductor hallucis?

Answer 22

Transverse head originates from the deep transverse metatarsal ligament. Oblique head originates from the base of metatarsals 2-4 which inserts into the base of the hallux. It adducts the big toe and is innervated by the lateral plantar nerve.

Question 23

What is the flexor digit minimi?

Answer 23

Arises laterally from the metatarsal of the 5th toe and fibularis longus to the base of the phalange, innervated by the lateral plantar nerve.

Question 24

What is the course of the dorsal interossei muscles of the toe?

Answer 24

Unipennate muscle which Originates and attaches to the base of the metatarsals 2-5 and angled towards the midline, and responsible for ABDUCTION. Innervated by the lateral plantar nerve.

Question 25

What is the exception to the dorsal interossei muscles?

Answer 25

The dorsal interossei muscles of the 2nd toe have 2 on either side, and are innervated by the deep fibular nerve and the lateral plantar nerve.

Question 26

What is the course for the proximal interossei muscles?

Answer 26

Unioennate muscle which Originates and attaches to the metatarsals 3-5 for adduction and is innervated by the lateral plantar nerve.