L17: Muscles of the Leg and Foot

Question 1

Muscles in the anterior compartment of the leg (crus)?

Answer 1

1. tibialis anterior
2. extensor digitorum longus
3. extensor hallucis longus
4. fibularis tertius

Question 2

muscles in the lateral compartment of leg?

Answer 2

1. fibularis longus

2. fibularis brevis

Question 3

muscles in posterior compartment of leg?

Answer 3

1. Gastrocnemius
2. Soleus
3. Plantaris
4. Popliteus
5. Tibialis posterior
6. Flexor digitorum longus
7. Flexor hallucis longus

Question 4

what action does the anterior compartment of the leg perform?

Answer 4

• dorsiflex at ankle

- extend toes

Question 5

origin and insertion of extensor digitorum longus?

Answer 5

origin: anterior tibia and fibula
insertion: distal phalanx 2nd -5th toes

Question 6

origin/insertion of fibularis tertius?

Answer 6

origin: anterior tibia
insertion: bast of 5th metatarsal

Question 7

origin/insertion of extensor hallucis longus?

Answer 7

origin: anterior fibula
insertion: distal phalanx 1st toe

Question 8

tibialis anterior is the strongest ____?

Answer 8

dorsiflexor

Question 9

origin/insertion of tibialis anterior?

Answer 9

origin: anterior tibia
insertion: base of 1st metatarsal and medial cuneiform

Question 10

action of lateral leg compartment muscles (fibularis longus/brevis)

Answer 10

• ankle eversion

- weak plantar flexion

Question 11

Origin of medial head of gastrocnemius?

Answer 11

medial condyle of femur

Question 12

origin of lateral head of gastrocnemius?

Answer 12

lateral femoral condyle

Question 13

origin of soleus?

Answer 13

proximal tibia and fibula

Question 14

origin of plantaris

Answer 14

superior lateral femoral condyle

Question 15

what are the triceps surae? what action?

Answer 15

• gastrocnemius and soleus

- plantar flexors

Question 16

origin/insertion of popliteus?

Answer 16

lateral femoral condyle > post proximal tibia

Question 17

action of tibialis posterior? *

Answer 17

• primary inverter

- dynamic stabiliser of medial longitudinal arch

Question 18

origin/insertion of tibialis posterior?

Answer 18

posterior tibia > metatarsals 2-4 and all tarsals except talus and calcaneus

Question 19

origin/insertion of flexor digitorum longus?

Answer 19

posterior tibia > distal phalanx digits 2-5

Question 20

origin/insertion flexor hallucis longus?

Answer 20

posterior fibula > 1st toe (hallux)

Question 21

why can’t the tibiofemoral joint act as a pure hinge joint?

Answer 21

• the difference in length of the articular surface area of medial and lateral femoral condyles
• results in some rotation occurring during flexion-extension

Question 22

what happens to the femur during weight-bearing sit to stand?

Answer 22

• femur rotates medially near full extension = screw home mechanism

Question 23

comparison of muscle group strength?

Answer 23

plantar flexor muscle mass > dorsiflexors

• greater PF leverage (calcaneal tuberosity)
• plantarflexion > 3x dorsiflexion peak torque

Question 24

plantarflexion __x> than dorsiflexion peak torque?

Answer 24

3x

Question 25

inversion strength is equal to?

Answer 25

eversion strength

Question 26

what does the extensor digitorum brevis extend?

Answer 26

• MTP, PIP, DIP of only toes 2-4

Question 27

what does extensor hallucis brevis extend?

Answer 27

MTP of the hallux

Question 28

what is plantar fascia?

Answer 28

• thickening of deep fascia of the foot

- encloses the plantar muscles

Question 29

origin/insertion of plantar fascia?

Answer 29

• medial process of tuberosity of calcaneus > 1st and 5th metatarsals
• phalanges
• skin

Question 30

function of plantar fascia?

Answer 30

• stabilisation of skin on sole
• support shape of foot and arches
• twice as strong as any other ligament in the foot

Question 31

stretch and recoil of plantar fascia and other plantar ligaments can save __% of the cost of running?

Answer 31

17%