Muscles of the Posterior compartment of the leg

Question 1

What is the collective function of muscles in the Posterior compartment of the leg?

Answer 1

plantarflex and invert the foot.

Question 2

Which muscles make up the Posterior compartment of the leg?

Answer 2

Gastrocnemius, Plantaris, Soleus, Popliteus, Tibialis Posterior, Flexor Digitorum Longus and Flexor Hallucis Longus.

Question 3

What are the layers the Posterior compartment of the leg is split into?

Answer 3

Superficial

Deep

Question 4

Which muscles are part of the Superficial layer?

Answer 4

Gastrocnemius, Plantaris, Soleus,

Question 5

What are the two bursae associated with the Calcaneal tendon called, what is their function and where are they?

Answer 5

To minimise friction during movement, there are two bursae (fluid filled sacs) associated with the calcaneal tendon:
Subcutaneous calcaneal bursa – lies between the skin and the calcaneal tendon.
Deep bursa of the calcaneal tendon – lies between the tendon and the calcaneus.

Question 6

Where is the origin of Gastrocnemius?

Answer 6

The lateral head originates from the lateral femoral condyle, and medial head from the medial femoral condyle.

Question 7

Where does the Gastrocnemius insert?

Answer 7

In the lower part of the leg, the muscle belly combines with the soleus to from the calcaneal tendon, with inserts onto the calcaneus.

Question 8

What are the actions of the Gastrocnemius?

Answer 8

It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there.

Question 9

What innervates the Gastrocnemius?

Answer 9

Tibial nerve.

Question 10

Where is the origin of Plantaris?

Answer 10

Originates from the lateral supracondylar line of the femur.

Question 11

Where does Plantaris insert?

Answer 11

The muscle descends medially, condensing into a tendon that runs down the leg, between the gastrocnemius and soleus. The tendon blends with the calcaneal tendon.

Question 12

What are the actions of Plantaris?

Answer 12

It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there. It is not a vital muscle for these movements.

Question 13

What innervates Plantaris?

Answer 13

Tibial nerve.

Question 14

Where is the origin of Soleus?

Answer 14

Originates from the soleal line of the tibia and proximal fibular area.

Question 15

Where does Soleus insert?

Answer 15

The muscle narrows in the lower part of the leg, and joins the calcaneal tendon.

Question 16

What is the action of Soleus?

Answer 16

Plantarflexes the foot at the ankle joint.

Question 17

What innervates Soleus?

Answer 17

Tibial nerve.

Question 18

What is the Calcaneal tendon also known as?

Answer 18

The Achilles tendon.

Question 19

What are the symptoms and possible causes of a Achilles tendon rupture.

Answer 19

It’s a partial or complete tear of the tendon.
The injury is usually sustained during forceful plantarflexion of the foot. The patient will be unable to plantarflex the foot against resistance, and the affected foot will be permanently dorsiflexed. The soleus and gastrocnemius can contract to form a lump in the calf region.

Question 20

Which muscles make up the Deep layer in the Posterior compartment of the leg?

Answer 20

Popliteus, Tibialis Posterior, Flexor Digitorum Longus and Flexor Hallucis Longus.

Question 21

Which bursa lies between the popliteal tendon and the posterior surface of the knee joint?

Answer 21

popliteus bursa.

Question 22

Where is the origin of Popliteus.

Answer 22

Originates from the lateral condyle of the femur and the posterior horn of the lateral meniscus.

Question 23

Where does the Popliteus insert?

Answer 23

It runs inferomedially towards the tibia and inserts above the origin of the soleus muscle.

Question 24

What is the action of Popliteus?

Answer 24

Laterally rotates the femur on the tibia – ‘unlocking’ the knee joint so that flexion can occur.

Question 25

What innervates Popliteus?

Answer 25

Tibial nerve.

Question 26

Where is the origin of Tibialis Posterior?

Answer 26

Originates from the interosseous membrane between the tibia and fibula, and posterior surfaces of the two bones.

Question 27

Where does Tibialis Posterior insert?

Answer 27

The tendon enters the foot posterior to the medial malleolus, and attaches to the plantar surfaces of the medial tarsal bones.

Question 28

What are the actions of Tibialis Posterior?

Answer 28

Inverts and plantarflexes the foot, maintains the medial arch of the foot.

Question 29

What innervates Tibialis Posterior?

Answer 29

Tibial nerve.

Question 30

Where is the origin of Flexor Digitorum Longus?

Answer 30

Originates from the medial surface of the tibia.

Question 31

Where does Flexor Digitorum Longus insert?

Answer 31

Attaches to the plantar surfaces of the lateral four digits.

Question 32

What is the action of Flexor Digitorum Longus?

Answer 32

Flexes the lateral four toes.

Question 33

What innervates Flexor Digitorum Longus?

Answer 33

Tibial nerve.

Question 34

Where is the origin of Flexor Hallucis Longus?

Answer 34

Originates from the posterior surface of the fibula.

Question 35

Where does Flexor Hallucis Longus insert?

Answer 35

Attaches to the plantar surface of the phalanx of the Hallux.

Question 36

What is the action of Flexor Hallucis Longus?

Answer 36

Flexes the Hallux.

Question 37

What innervates Flexor Hallucis Longus?

Answer 37

Tibial nerve.