Superficial Fibular Nerve Flashcards
What are the roots of the superficial fibular nerve?
L4-S1
What are the motor functions of the superficial fibular nerve?
Innervates the muscles in the lateral compartment of the leg
What are the sensory functions of the superficial fibular nerve?
Supplies the vast majority of the skin over the dorsum of the foot, apart from the webbing between the hallux and the second digit
Supplies the anterior and lateral aspect of the inferior third of the leg
What does the superficial fibular nerve arise from?
The terminal branch of the common fibular nerve
Where does the superficial fibular nerve arise?
At the neck of the fibula
What is the anatomical course of the superficial fibular nerve?
It descends between the fibularis muscles and the lateral side of the extensor digitorum longus
The nerve continues its descent
When it reaches the lower third of the leg, it pierces the deep crural fascia
What does the superficial fibular nerve give rise to after it arises?
Motor branches which supply the fibularis longus and brevis
What does the nerve do as it continues its descent down the neck of the fibula?
Provides sensory innervation to the anterolateral aspect of the leg
When does the superficial fibular vein terminate?
When it pierces the deep crural fascia
How does the superficial fibular nerve terminate?
By dividing into the medial and intermedial dorsal cutaneous nerves
What do the medial and intermedial dorsal cutaneous nerves do?
Enter the foot to innervate the majority of its dorsal surface
What muscles do the superficial fibular nerve supply?
Those of the lateral compartment of the lower leg
What are the muscles of the lateral compartment of the lower leg?
The fiburlaris longus and the fibularis brevis
What do the muscles of the lateral compartment of the lower leg do?
Act to evert the foot, and thus act at the subtalar joint
Weakly contribute to plantarflexion
What is eversion?
The action of turning the foot outwards
What is plantarflexion mainly carried out by?
The gasocnemius and soleus muscles
What does the superficial fibular nerve innervate directly?
The skin over the anterolateral leg
How does the superficial fibular nerve indirectly innervate?
Via the medial and intermedial dorsal cutaneous nerves
What do the medial and intermedial dorsal cutaneous nerves innervate?
The skin of the dorsum of the foot (except the webbed space between the hallanx and the 2nd digit)
What are the dermatomes that correspond to the areas innervated by the superficial fibular nerve?
L5 and S1
What are the relatively commonly pathologies involving damage to the superficial fibular nerve?
Entrapment
Direct damage
What can superficial peroneal nerve entrapment cause?
Pain and paresthesia over the lower leg and dorsum of the foot
What does entrapment frequently result from?
Ankle sprains or twisting of the ankle
Why does twisting the ankle cause superficial peroneal nerve entrapment?
It causes the nerve to stretch in the lower leg
Where does nerve entrapment commonly occur?
At the point where the nerve exits the deep fascia of the leg- the nerve becomes compressed by the fascia
What is used to provide relief from the symptoms when the superficial fibular nerve is compressed as it exits the deep fascia of the leg?
Surgical decompression of the nerve
How can the superficial fibular nerve be damaged?
A fracture of the fibula
A perforating wound to the lateral side of the leg
What may injury to the superficial fibular nerve result in?
Loss of eversion
A loss of sensation over the majority of the dorsum of the foor, and the anterolateral aspect of the lower leg could result
Why may damage to the superficial fibular nerve result in a loss of eversion?
As the muscles that the superficial fibular nerve innervates are evertors
