Posterior Compartment Leg Muscles (Quiz/Exam 3)

Question 1

What are the 3 superficial posterior compartment muscles of the leg?

Answer 1

1) gastrocnemius
2) soleus
3) plantaris

Question 2

There are 3 superficial posterior compartment muscles of the leg: gastrocnemius, soleus, and plantaris. They all do….

Answer 2

plantar flexion

Question 3

What is the origin/proximal attachment for the lateral head of the gastrocnemius?

Answer 3

lateral aspect of the lateral condyle of the femur

Question 4

What is the origin/proximal attachment of the medial head of the gastrocnemius?

Answer 4

popliteal surface of the femur, superior to medial condyle

Question 5

What is the insertion/distal attachment for the gastrocnemius?

Answer 5

posterior surface of calcaneus via calcaneal tendon

Question 6

What innervates the gastrocnemius?

Answer 6

tibial n.

Question 7

What are the actions of the gastrocnemius?

Answer 7

-plantar flexes ankle when knee is extended
-raises heel during walking
-flexes leg at the knee joint

note: it is not active when the knee is flexed, it needs to be extended to be able to plantar flex

Question 8

Is the gastrocnemius a type 1 or 2 muscle? What does this mean?

Answer 8

type 2
-fast twitch muscle /white muscle
-produces rapid movements during running and jumping

Question 9

Is the soleus a type 1 or type 2 muscle? What does this mean?

Answer 9

type 1
-red muscle
-fatigue resistant muscle
-slow twitch muscle
-capable of sustained contraction
-good for strolling and standing

Question 10

What are the origins of the soleus?

test q

Answer 10

-posterior aspect of the head of the fibula
-superior quarter of posterior surface of fibula soleal line
-medial border of tibia

Question 11

What is the insertion of the soleus?

Answer 11

posterior surface of calcaneus via calcaneal tendon

Question 12

What innervates the soleus?

Answer 12

tibial n.

Question 13

What are the actions of the soleus?

Answer 13

-plantar flexes ankle independent of the position of the knees
-steadies leg on foot

Question 14

Which muscle is absent in 5-10% of people?

test q

Answer 14

plantaris

Question 15

What is the origin of the plantaris?

Answer 15

-inferior end of lateral supracondylar line of femur
-oblique popliteal ligament

Question 16

What is the insertion/distal attachment of the plantaris?

Answer 16

posterior surface of calcaneus via calcaneal tendon

Question 17

What innervates the plantaris?

Answer 17

tibial n.

Question 18

What are the actions of the plantaris?

Answer 18

weakly assists gastrocnemius in plantar flexing ankle

Question 19

What is the origin/proximal attachment of the popliteus?

Answer 19

lateral surface of the lateral condyle of the femur and lateral meniscus

Question 20

What is the insertion/distal attachment for the popliteus?

Answer 20

posterior surface of the tibia, superior to the soleal line

Question 21

What innervates the popliteus?

Answer 21

tibial n.

Question 22

What are the actions of the popliteus?

Answer 22

-weakly flexes knee and unlocks it by rotating femur on a fixed tibia
-medially rotates tibia of unplanted limb

Question 23

What is the origin/proximal attachment for the flexor hallucis longus?

Answer 23

inferior 2/3 of posterior surface of fibula and inferior part of interosseous membrane

Question 24

What is the insertion/distal attachment for the flexor hallucis longus?

Answer 24

base of distal phalanx of the great toe

Question 25

What innervates the flexor hallucis longus?

Answer 25

tibial n.

Question 26

What are the actions of the flexor hallucis longus?

Answer 26

-flexes great toe at all joints
-weakly plantar flexes ankle
-supports medial longitudinal arch of the foot

Question 27

What is the origin/proximal attachment of the flexor digitorum longus?

Answer 27

medial part of posterior surface of the tibia inferior to the soleal line by a broad tendon to the fibula

Question 28

What is the insertion/distal attachment for the flexor digitorum longus?

Answer 28

bases of distal phalanges of lateral 4 digits

Question 29

What innervates the flexor digitorum longus?

Answer 29

tibial n.

Question 30

What are the actions of the flexor digitorum longus?

Answer 30

-flexes lateral 4 digits
-plantar flexes ankle
-supports longitudinal arch of foot

Question 31

What is the origin/proximal attachment for the tibialis posterior?

Answer 31

-interosseous membrane
-posterior surface of tibia inferior to soleal line
-posterior surface of fibula

Question 32

What is the insertion/distal attachment for the tibialis posterior?

Answer 32

-tuberosity of navicular, cuneiform, and cuboid
-bases of 2nd, 3rd, and 4th metatarsals

Question 33

What innervates the tibialis posterior?

Answer 33

tibial n.

Question 34

What are the actions of the tibialis posterior?

Answer 34

plantar flexes ankle and inverts the foot (its a strong muscle)