MSK Muscles of the leg

Question 1

Name the muscles in the anterior compartment of the leg

Answer 1

Tibialis anterior
Fibularis tertius
Extensor digitorum longus
Extensor hallucis longus

Question 2

What are the attachments and actions of the tibialis anterior?

Answer 2

Located on lateral surface of tibia

Originates from lateral tibia and attaches to medial cuneiform and base of metatarsal 1

Actions:
Strongest dorsiflexor of foot
Inverts foot

Question 3

How would you test the power of tibialis anterior?

Answer 3

Ask the patient to stand on their heels

Question 4

What are the attachments and actions of the extensor digitorum longus?

Answer 4

Lateral and deep to tibialis anterior

Originates from lateral condyle of tibia and medial surface of fibula, fibres converge to a tendon which inserts onto each of the 4 toes

Actions:
Extension of lateral 4 toes
Dorsiflexion of foot

Question 5

What are the attachments and actions of the extensor hallucis longus?

Answer 5

Located deep to tibialis anterior and extensor digitorum longus

Originates from medial surface of fibular shaft and tendon crosses anterior to ankle joint and attaches to base of distal phalanx of great toe

Actions:
Extension of great toe
dorsiflexion

Question 6

What are the attachments and actions of the fibularis tertius?

Answer 6

Not present in all individuals

Originates from the most inferior part of the extensor digitorum longus, the tendon descends with the EDL until the foot where the tendon diverges to attach to metatarsal 5

Actions:
Eversion and dorsiflexion

Question 7

What is is innervation and blood supply to the anterior leg muscles?

Answer 7

Deep fibular nerve (L4-5)

Anterior tibial artery

Question 8

What is the clinical sign of damage to the deep fibular nerve?

Answer 8

Footdrop due to paralysis of the anterior leg muscles
There is unopposed pull of the plantarflexor muscles producing permanent plantarflexion

The patient will have difficulty walking so to overcome this they will do the ‘eversion flick’, flicking the affected foot out whilst walking

Question 9

Name the muscles in the lateral compartment of the leg

Answer 9

Fibularis longus and brevis

Question 10

What are the attachments and actions of the fibularis longus?

Answer 10

Most superficial of the two

Originates from lateral and superior surface of fibula and lateral tibial condyle. The fibres converge into a tendon which enters foot posterior to lateral malleolus. Tendon crosses under the foot and attaches to medial cuneiform and base of metatarsal 1 on medial side

Actions:
Eversion and plantarflexion
Supports arches of the foot

Question 11

What are the attachments and actions of the fibularis brevis?

Answer 11

Deeper than fibularis longus

Originates from inferior and lateral surface of fibular shaft, descends with the fibularis longus tendon and travels into foot posterior to lateral malleolus. Attaches to metatarsal 5

Actions:
Eversion of foot

Question 12

What is the innervation of the lateral muscles of the leg?

Answer 12

Superficial fibular nerve (L4-S1)

Question 13

How can you locate the superficial fibular nerve during dissection?

Answer 13

Use the fibularis longus as a landmark
There is a gap between the parts of the fibularis longus that originate from fibular head and neck - the common fibular nerve passes through this gap then bifurcates into deep and superficial branches

Question 14

Name the superficial and deep muscles in the posterior compartment of the leg

Answer 14

Superficial muscles:
Gastrocnemius
Plantaris
Soleus

Deep muscles:
Popliteus
Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus

Question 15

Where do the superficial muscles of the posterior region of the leg insert?

Answer 15

They insert into the calcaneus of the foot via the calcaneal tendon

Question 16

What are the bursae in the calcaneal tendon?

Answer 16

Subcutaneous calcaneal bursa - between skin and calcaneal tendon
Deep bursa of the calcaneal tendon - between tendon and calcaneus

Question 17

Superficial

What are the attachments and actions of the gastrocnemius?

Answer 17

Most superficial, comprises mainly of fast twitching muscle fibres which produce forceful movements such as running and jumping

Lateral + medial head originate from lateral +medial femoral condyle. The muscle belly combines with soleus and inserts into calcaneus

Actions:
flexes knee
plantarflexion

Question 18

Superficial

What are the attachments and actions of the plantaris?

Answer 18

Small muscle with long tendon

Originates from lateral supracondylar line of femur and descends medially between gastrocnemius and soleus.

Actions:
flexes knee
plantarflexion

Question 19

Superficial

What are the attachments and actions of the soleus?

Answer 19

Deep to gastrocnemius, large and flat like a sole fish

Originates from soleal line of tibia and proximal fibular, narrows in the lower leg and joins the calcaneal tendon

Actions:
plantarflexion

Question 20

What is the innervation of the posterior compartment of the leg?

Answer 20

Tibial nerve

Question 21

How does the calcaneal tendon get ruptured and what is the treatment?

Answer 21

Caused by forceful plantarflexion
The affected foot will be permanently dorsiflexed
Treatment is usually non-surgical

Question 22

What are the attachments and actions of the popliteus?

Answer 22

Forms base of the popliteal fossa
There is a popliteal bursa between the popliteal tendon and the posterior surface of knee joint

Originates from posterior surface of proximal tibia and fibres pass up to the lateral condyle of femur

Actions:
Laterally rotates femur which unlocks the knee so flexion can occur

Question 23

What are the attachments and actions of the tibialis posterior?

Answer 23

Deepest of the 4 deep posterior

Originates from interosseous membrane and posterior surfaces of tib and fib, enters the foot posterior to medial malleolus and attaches to plantar surfaces of medial tarsal bones.

Actions:
Inverts and plantarflexes foot
Maintains the medial arch

Question 24

What are the attachments and actions of the flexor digitorum longus?

Answer 24

Smaller than flexor hallucis longus, located medially

originates from medial surface of tibia and attaches to plantar surface of lateral 4 digits

Actions:
flexes lateral 4 toes

Question 25

What are the attachments and actions of the flexor hallucis longus?

Answer 25

Located laterally

Originates from posterior surface of fibula and attaches to plantar surface of the phalanx of the great toe

Actions:
flexes the great toe