Lecture: The Leg

Question 1

popliteal fossa
* what is it
* what does it contain
* what are its borders

Answer 1

diamond shaped indentation on the back of knee
superolateral border: medial border of biceps femoris
superomedial border: lateral border of semimembranosus
inferolateral: medial border of lateral head of gastrocnemius
inferomedial: lateral border of medial head of gastrocnemius

contains (lateral to medial): common peroneal/fibular nerve, tibial nerve, popliteal vein, artery;

Question 2

What is the genicular anastomosis?
* What is part of it?

Answer 2

network of vessels surrounding knee capable of maintaining circulation of leg in full knee flexion

all branch off popliteal artery
* superior lateral genicular artery
* inferior lateral genicular artery
* superior medial genicular artery
* inferior medial genicular artery
* middle genicular artery

Question 3

arterial supply of leg

Answer 3

femoral artery –> popliteal artery –> anterior and posterior tibial artery

anterior tibial artery projects anteriorly by passing between fibula and tiiba at superior to interosseous membrane

posterior tibial artery travells slightly medially but down the posterior side of the leg.

the fibular artery branches off the posterior tibial artery and travels laterally. branching happens just beneath popliteal fossa

Question 4

3 main nerves of the leg

Answer 4

sciacic nerve lateral branch: common fibular nerve –> anterior compartment of leg; has deep and superficial branch

superficial branch travels laterally

deep branch travels medially

sciatic nerve medial branch: tibial nerve

Question 5

What does the superficial common peroneal/fibular nerve supply?

What can occur if this nerve is cut?

Answer 5

fibularis longus and fibularis brevis
lateral compartment muscles of leg

abolishment of eversion; weak plantarflexion

Question 6

What muscles does the deep common peroneal/fibular nerve supply?

What actions would be weak or paralyzed?

Answer 6

• tibialis anterior
• extensor hallucis longus
• extensor digitorum longus
• fibularus tertius

paralysis: big toe extension, ankle dorsiflexion, extends lateral 4 digits,

weakness: ankle inversion

Question 7

What muscles do the tibial nerve supply?

What actions would be weak or not occur at all due to denervation of the tibial nerve?

Answer 7

gastrocnemius
plantaris
popliteus
soleus
flexor digitorum longus
flexor hallucis longus
tibialis posterior

Paralysis of plantarflexion, toe flexion
Weak: inversion

Question 8

Describe the different compartments of the leg. be able to draw it out

Question 9

Describe the insertion sites of the antero-lateral and antero-medial leg muscles viewed on the dorsal surface of the foot

Question 10

At what joint does eversion/inversion and plantarflexion/dorsiflexion occur at?

Answer 10

eversion/inversion: subtalar joint (talus and calcaneus)

plantarflexion/dorsiflexion: fibula tibia and talus (true ankle joint)

Question 11

What is the importance of the lateral compartment of the leg

Answer 11

Evert the foot at the ankle (prevent excessive inversion)

Question 12

How does the gastrocnemius and soleus differ

Answer 12

gastrocnemius: Plantar flexes the foot at the ankle (leg extended); Flexes the leg at the knee

soleus: Plantar flexes the foot at the ankle (independent of leg extension); High percentage of slow-twitch fibres

Question 13

Describe a branch of the femoral artery that continues on the anterior surface of the femur

Answer 13

profunda femoris artery