Lower Limb - Anterior Compartment of the Leg (1)

Question 1

Name the four muscles of the anterior compartment of the leg.

Answer 1

Tibialis Anterior
Extensor Digitorum Longus
Extensor Hallucis Longus
Fibularis Tertius

Question 2

Describe the superior extensor retinaculum of the ankle.

Answer 2

This is a strong, broad band of deep fascia, passing from the fibula to the tibia, proximal to the malleolus.

Question 3

Describe the inferior extensor retinaculum of the ankle.

Answer 3

This is Y-shaped band of deep fascia, with the trunk of the Y being the lateral attachment to the calcaneus.

Question 4

What is the origin and insertion of the tibialis anterior?

Answer 4

Origin: Lateral surface of tibia and interosseous membrane
Insertion: Base of 1st metatarsal

Question 5

What is the origin and insertion of the extensor digitorum longus?

Answer 5

Origin: Medial surface of fibula and interosseous membrane
Insertion: Middle and distal phalanges of lateral 4 digits

Question 6

What is the distal attachment of fibularis tertius?

Answer 6

Base of 5th metatarsal

Question 7

What connects the extensor digitorum longus to the fibularis tertius near their distal attachments?

Answer 7

Common synovial sheath covering all 5 tendons.

Question 8

What is the innervation to all muscles of the anterior compartment? Where does this nerve come from?

Answer 8

Deep fibular nerve. The sciatic nerve branches into the Common Fibular and the Tibial nerves at the popliteal fossa. The Common Fibular then branches into the Superficial Fibular and the Deep Fibular nerves.

Question 9

Looking at the anterior surface of the ankle, as the tendons of the anterior compartment pass beneath the extensor retinaculi, what is their order from medial to lateral?

Answer 9

Tibialis Anterior, Extensor Hallucis Longus, Extensor Digitorum Longus, Fibularis Tertius.

Question 10

What is the course of the deep fibular nerve? Which artery does it accompany?

Answer 10

The deep fibular is a branch of the common fibular. It accompanies the anterior tibial artery.

Question 11

What is the clinical term for a patient with a lesion to the deep fibular nerve?

Answer 11

Foot drop.

Question 12

What is the major artery of the anterior compartment, and what does its name change to as it crosses the ankle joint?

Answer 12

Anterior tibial artery –> becomes the dorsalis pedis (dorsal artery of the foot)