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Flashcards in Common Fibular nerve Deck (19):

Where does the common fibular nerve begin and where does it travel?

begins at apex of popliteal fossa
follows medial border of biceps femoris
continues in a lateral inferior direction - over lateral head of gastrocnemius
then gives rise to 2 cutaneous branches - innervate skin of leg


What happens to the common fibular nerve in the lateral leg?

nerve wraps around the neck of fibular
passing between attachments of fibularis longus muscle (lateral)
then terminates into superficial fibular and deep fibular nerves innervating skin of lateral leg


Which muscles does the common fibular nerve innervate?

short head of biceps femoris (part of hamstring muscles flexing the knee & extending hip)


Which muscle does the superficial fibular nerve innervate?

fibularis longus and brevis


Which muscles does the deep fibular nerve innervate?

muscles of the anterior compartment of the leg:
tibialis anteerior, extensor digitorum longus, extensor hallucis longus
they dorsiflex the foot, extend digits


What happens if the common fibular nerve is damaged?

the patient may loose the ability to dorsiflex (anterior compartment of leg), extend digits 9extensor digitorum & hallucis longus), and can't evert foot (fibularis longus & brevis)


Where do the branches of sensory nerve arise from the common fibular nerve?

when the common fibular nerve moves over the lateral head of the gastrocnemius


What are the sensory branches of the common fibular nerve?

1. sural commicating nerve
2. lateral sural cutaneous nerve


What does the sural commicating nerve innervate?

combines with a branch of tibial nerve to form sural nerve
innervates skin over lateral posterolateral leg


What does the lateral sural cutaneous nerve innervate?

skin over upper lateral leg


What is the sensory innervation of the superficial fibular nerve?

skin of the anterolateral leg & dorsum of the foot (except the skin between the first & second toe)


Which sensory region does the deep fibular nerve innervate?

skin between the 1st & 2nd toe


Clinical: how is the common fibular nerve usually damaged?

fracture of fibular / use of tight plaster cast


How can fracture of fibular cause damage to the common fibular nerve?

fracture of fibular can cause damage to common fibular nerve as the CFN wraps around the NECK of fibular - can cause nerve palsy (weakened function)


What will patient with common fibular nerve damage loose the ability to do? How will this appear?

lose ability to dorsiflex foot at ankle joint (anterior leg innervated by deep fibular nerve which is a branch of common fibular nerve)
foot appears permanently plantarflexed 'footdrop'


How else can you tell if a patient has common fibular damage?

characteristic gait as a result of footdrop
leg raised higher to lift up the plantar flexed foot


How else can you test for common fibular nerve damage in a patient?

loss of sensation over the dorsum (top) of the foot (deep fibular nerve)
and lateral side of the leg (common fibular nerve)


Which sections of the leg can still have sensation despite common fibular nerve damage and why?

medial side (supplied by saphenous nerve - branch of femoral)
heel & sole (tibial nerve - branch of sciatic)


Nerve roots, motor and sensory function

motor: innervates short head of biceps femoris directly and anterior & lateral compartment of the leg indirectly
sensory: skin of lateral leg and dorsum (top) of foot (deep and superficial fibular nerve and branches of sural nerve)