Lower limb

Question 1

Why is the tibia prone to fracture?

Answer 1

• Shaft is subcutaneous
• Unprotected anteromedially throughout its course
• Particularly slender in its lower third

Question 2

Why is the tibia commonly used for bone grafts?

Answer 2

Due to its extensive subcutaneous surface

Question 3

What is the interosseous membrane of the lower limb?

Answer 3

• Fibrous joint which unites the tibia & fibula
• Seperates muscles of anterior & posterior compartments
• Provides a site for muscle attachments

Question 4

What are the 2 foramina in the interosseous membrane and their functions?

Answer 4

• One for anterior tibial vessels

- One for perforating branch of fibular artery

Question 5

What muscles are contained in the anterior compartment of the leg?

Answer 5

• Tibialis anterior (most medial)
• Extensor digitorum longus
• Extensor hallucis longus
• Fibularis tertius

Question 6

What is the primary function of the anterior muscles in the leg?

Answer 6

Involved in extension at joints

Question 7

What movements can be produced at the ankle by contraction of tibialis anterior?

Answer 7

• Dorsiflexion of foot
• Inversion of foot
• Dynamic support of medial arch of foot

Question 8

Where do extrinsic & intrinsic extensors of the toes originate and insert?

Answer 8

Extrinsic= O: in the leg I: in the foot
Intrinsic= O: in the foot I: in the foot

Question 9

Name the extrinsic extensors of the toes

Answer 9

• Extensor hallucis longus

- Extensor digitorum longus

Question 10

What is the function of fibularis tertius?

Answer 10

• Dorsiflexion & eversion of foot

- Not present in all individuals

Question 11

What innervates the anterior compartment of the leg? What does it arise from?

Answer 11

Deep fibular nerve- branch from the common fibular nerve

Question 12

What arises from the popliteal artery? Where does it travel?

Answer 12

Anterior tibial artery- passes from the posterior to anterior compartment of the leg via a hiatus in the interosseous membrane supplies structures in anterior compartment

Question 13

Name the muscles in the lateral compartment of the leg, where do their tendons pass?

Answer 13

• Fibularis (peroneus) longus
• Fibularis (peroneus) brevis
• Tendons pass posterior to the lateral malleolus

Question 14

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

Answer 14

Superficial fibular nerve L5, S1

Question 15

What are the consequences of injuring the common fibular nerve?

Answer 15

• Foot drop: dorsiflexion of the foot compromised- foot drags during walking
• Sensory loss to dorsal surface of foot & portions of anterior lower lateral leg

Question 16

What are the actions of fibulas longus & brevis?

Answer 16

Longus= Eversion & plantarflexion of foot, supports arches
Brevis= Eversion of foot

Question 17

How is the posterior compartment of the leg divided?

Answer 17

Into superficial and deep sub-compartments by the transverse inter muscular septum

Question 18

What is contained in the deep compartment of the posterior leg?

Answer 18

• Posterior tibial artery
• Tibial nerve
• Popliteus
• Flexor digitorum longus
• Flexor hallucis longus
• Tibialis posterior

Question 19

What are the superior & inferior extensor retinaculum?

Answer 19

S=Thickening of the fascia that extends across the anterior leg proximal to the lateral& medial malleoli. Attaches to fibula and to tibia.
I= Y shaped band from anterior calcaneus extends medially to ankle, where it divides into two. Upper retinaculum attaches to medial malleolus. Lower passes around the medial side of the foot and attaches to the plantar aponeurosis.

Question 20

What are the functions of the superior & inferior fibular (peroneal) retinaculum?

Answer 20

S=Keeps tendons of the fibularis longus & fibularis brevis in place as they pass posterior to the lateral malleolus.
I=Holds the tendons of fibularuis longus & fibularis brevis against the calcaneus.

Question 21

How is the calcaneal tendon formed?

Answer 21

• Joining of tendons of Soleus & gastrocnemius

- Tendon of plantaris muscle inserts into medial border

Question 22

What is contained in the superficial compartment of the posterior leg?

Answer 22

• Gastrocnemius
• Plantaris
• Soleus