Nerves - Deep Fibular

Question 1

Nerve roots of the deep peroneal?

Answer 1

L4 - S1

Question 2

Motor function?

Answer 2

Muscles of the anterior compartment of the leg, as well as some intrinsic muscles of the foot.

Question 3

Sensory function?

Answer 3

Supplies the triangular region between the 1st and 2nd toes.

Question 4

Anatomical course?

Answer 4

The deep fibular nerve is a terminal branch of the common fibular nerve.

Arises in the lateral compartment of the leg, between the fibularis longus muscle and the neck of the fibula.

The nerve travels medially and enters the anterior compartment of the leg. It is accompanied by the anterior tibial artery. It descends in a plane initially between the tibialis anterior and extensor hallucis longus.

During its descent, it is initially lateral, then anterior and finally medial to the anterior tibial artery.

At the ankle the deep fibular nerve travels underneath the extensory retinaculum and divides within the dorsum of the foot into two branches:
1) Lateral branch - innervates the extensor digitorum brevis and the extensor hallucis brevis.

2) Medial branch - innervates the skin of the webbed space between the 1st and 2nd toes.

Question 5

Clinical relevance: footdrop

Answer 5

Deep fibular nerve can become entrapped or compressed during its course in the anterior compartment.

Causes paralysis of the muscles with the anterior compartment - patient may not be able to dorsiflex.

Person will experience difficulty clearing the floor in the swinging phase - the foot will also slap down on the floor when walking, because it can’t be controlled on descent.

Aetiology of compression:

1) Excessively used anterior compartment legs.
2) Tight-fitting shoes - compresses nerve beneath the extensor retinaculum. Occurs when wearing ski boots. Person may experience pain in the dorsum of the foot.