Lower limb 4 - The leg

Question 1

What is the tibia?

Answer 1

One of the long bones of the leg.

It is triangular in cross section having medial, lateral and posterior surfaces.

Question 2

Where is the most common sites for acute osteomyelitis?

Answer 2

upper end of tibial shaft

Question 3

What is acute osetomyelitis?

Answer 3

infection/inflammation of the bone

Question 4

Why is the tibia the commonest long bone to be fractured and to suffer compound injury?

Answer 4

the shaft of the tibia is subcutaneous and unprotected anteromedially throughout it’s course and is particularly slender in its lower third.

Question 5

Why is the tibia a highly accessible donor site for bone grafts?

Answer 5

Due to it’s extensive subcutaneous surface

Question 6

What is the fibula?

Answer 6

second long bone present in the leg

Question 7

What is the interosseous membrane? (3)

Answer 7

a form of fibrous joint which unites the tibia and fibula

it separates the muscles of the anterior and posterior compartment of the leg

provides a site for muscle attachment

Question 8

What is the function of the 2 foramina in the interosseous membrane?

Answer 8

Upper foramina - allows passage of anterior tibial vessels

Lower foramina - allows the passage of anterior perineal vessels

Question 9

What four muscles are involved in the anterior compartment of the the leg?

Answer 9

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

Question 10

What is the function of the retinaculum in a limb?

Answer 10

a band structure that holds the organ part in place

Question 11

What are the anterior compartment muscles primarily involved in?

Answer 11

extension at joints

Question 12

What is the most medial muscle in the anterior compartment of the leg?

Answer 12

tibialis anterior

Question 13

What are the extrinsic extensors of the toes?

Answer 13

extensor hallucis longus

extensor digitorum longus

Question 14

Where is the fibularis (peroneus) tertius found and is it present in all individuals?

Answer 14

deep to extensor hallucis longus

Question 15

How is the anterior tibial artery exposed?

Answer 15

by retracting the extensor digitorum longus

Question 16

Where does the anterior tibial artery arise from and where does it pass from?

Answer 16

the popliteal artery

from the posterior and anterior compartment of the leg via a hiatus in the interosseous membrane

Question 17

What is the deep fibular nerve a branch of and what muscles of which compartment does it innervate?

Answer 17

branch of common fibular nerve

innervates muscles of the anterior compartment

Question 18

What are the two muscles in the lateral compartment of the leg?

Answer 18

1. fibularis (peroneus) longus

2. fibularis (peroneus) brevis

Question 19

What are the fibular muscles tightly invested with and where do their tendons pass?

Answer 19

with the deep fascia of the leg

their tendons pass posterior to the lateral malleolus

Question 20

Why is the common fibular nerve vulnerable to injury?

Answer 20

as it courses around the neck of the fibula which an area that is vulnerable to fracture

Question 21

What are the consequences of injuring the common fibular nerve at this point? (6)

Answer 21

1. lose ability to dorsiflex foot at ankle joint
2. foot drop (foot appears permanently plantar flexed)
3. foot drop gait
4. loss of sensation over dorsum of foot
5. loss of sensation on lateral side of leg
6. innervation is preserved on medial side of the leg

Question 22

What is the posterior compartment of the leg divided into and what by?

Answer 22

superficial sub-compartment

deep sub-compartment

by transverse inter muscular septum

Question 23

What artery and nerve does the deep sub-compartment of the posterior compartment of the leg contain?

Answer 23

posterior tibial artery

tibial nerve

Question 24

What are the four muscles involved in the deep sub-compartment of the posterior compartment of the leg?

Answer 24

1. popliteus
2. flexor digitorum longus
3. flexor hallucis longus
4. tibialis posterior

Question 25

Where do the tendons of tibialis posterior, flexor digitorum longus and flexor hallucis longs pass?

Answer 25

pass posterior to the medial malleolus

order - Tom Dick and Nervous Harry

Question 26

Where do the tibial nerve and posterior tibial artery pass in relation to the medial malleolus, flexor digitorum longs and flexor hallucis longs?

Answer 26

posterior to medial malleolus

between flexor digitorum longus

Flexor hallucis longus

Tom, Dick and Nervous Harry