Leg

Question 1

What are the 2 bones of the leg?

Answer 1

Tibia- poor blood supply and is most common long bone fractured

Fibula

Question 2

Describe the relationship of the crural fascia to its tibial attachments and to the retinacula of the foot

Superior (extensor) retinaculum
Inferior (extensor) retinaculum
Flexor retinaculum
Superior/Inferior Peroneal retinaculum

Answer 2

The crural Fascia attaches to the anterior and medial borders of the tibia- continuous with the periosteum

Forms the Retinacula in the foot:
-Superior (extensor) retinaculum –> Binds tendons in anterior crural compartment

• Inferior (extensor) retinaculum –> Y shaped
• Flexor retinaculum –> Binds tendons of deep posterior compartment
• Superior/Inferior Peroneal Retinacula –> Binds tendons of lateral crural compartment

Question 3

Describe the cutaneous innervation of the posterior superficial surface. Where does each nerve come from?

Answer 3

Lateral Sural Cutaneous Nerve- From common peroneal (fibular) nerve
Medial sural Cutaneous Nerve- From tibial nerve

*Note that the sural nerve runs with the lesser saphenous vein

Question 4

Describe the 3 muscles of the superficial posterior compartments and one tendon. Which muscle crosses two joints?

Answer 4

Gastrocnemius (medial and lateral)- crosses both knee and ankle joint. 2 heads form inferior boundaries of the popliteal fossa.

Plantaris
Soleus
Tendo Calcaneus (Achilles tendon)

Question 5

Describe the nerves of the superficial posterior compartments in terms of their innervation. What does it branch into (3 of them)?

Answer 5

Tibial Nerve- this supplies ll muscles in the posterior compartment.

Divides into the medial and lateral plantar nerves inferior and posterior to the medial malleolus

Gives off medial sural cutaneous nerve

Joins with communicating branch of common peroneal (fibular) nerve to form the Sural nerve

Question 6

Describe the blood supply to the superficial posterior compartment

Answer 6

Posterior Tibial Artery- Largest of the popliteal artery. Divides into the medial and lateral plantar arteries deep to origin of abductor hallucis.

Peroneal (Fibular) Artery- Most important branch of the posterior tibial artery. Supplies posterior and lateral compartments and popliteus muscles.

Question 7

Describe the 4 muscles of the deep posterior compartment. Which one is used for walking, running, and jumping? What are their main functions? Which muscle causes foot inversion?

Answer 7

Popliteus- Lies in the floor of the popliteal fossa

Flexor Digitorum Longus- Tendon passes posterior to medial malleolus and to the tendon of tibialis posterior. Plantar flexes foot at the ankle joint.

Flexor Hallucis Longus- Push off muscle for walking, jumping, and running

Tibialis posterior- Functions in plantar flexions and foot inversions.

Question 8

Describe the muscles of the deep posterior compartment in terms of their innervation

Answer 8

Tibialis Nerve

Question 9

Describe the blood supply to the deep posterior compartment

Answer 9

Posterior Tibial Artery

Question 10

Describe the 4 muscles of the anterior compartment. Which one causes foot inversion and which causes foot eversion?

Answer 10

Tibialis anrterior- Foot dorsiflexion and inversion. Paralysis leads to a “foot drop”.

Extensor digitorum longus- has 4 tendons for insertion, each of which inserts on an extensor expansion similar to the arrangement in the hand.

Extensor hallucis longus

Peroneus (fibularis) tertius- part of extensor digitorum longus. Foot dorsiflexion and eversion.

Question 11

Describe the muscles of the anterior compartment in terms of their innervation

Answer 11

Deep peroneal (fibular) nerve:
L4-5 to tibialis anterior
L5-S1 to remaining muscles

Question 12

Describe the muscles of the anterior compartment in terms of their functions

Answer 12

Toe extension

Ankle dorsifleion

Question 13

Describe the blood supply of the anterior compartment

Answer 13

Anterior Tibial Artery- smaller terminal branch of the popliteal artery. Begins at inferior border of popliteus muscle.

*Becomes dorsalis pedis artery at the ankle joint

Question 14

Describe the muscles of the lateral compartment

Answer 14

Peroneus (fibularis) longus

Peroneus (fibularis) brevis

Question 15

Describe the muscles of the lateral compartment in terms of their innervation and the spinal cord level

Answer 15

Superficial peroneal (fibular) nerve- deep to peroneus longus. Inserts on lateral tuberosity.

Spinal cord levels L5- S1-S5

Question 16

What is the blood supply of the lateral compartment of the leg

Answer 16

No major arteries in the lateral compartment.

Muscular branches arise from the peroneal artery- branch of the posterior tibial