Flashcards in Deep Fibular nerve Deck (15):
Nerve roots, motor & sensory function?
L4 & L5
Motor: muscles in anterior compartment of leg & some intrinsic foot muscles
Sensory: triangle region between 1st & second toes (webbing)
What is it a terminal branch of?
deep fibular (peroneal) nerve is a terminal branch of common fibular nerve
Which branch does the deep fibular nerve arise from?
sciatic nerve --> popliteal fossa --> common fibular nerve (wraps around neck of fibula) --> moves anterolaterally --> superficial and deep fibular nerve
Where does the deep fibular nerve arise from anatomically?
superolateral aspect of leg - between fibularis longus muscle and neck of fibula
Describe the course of travel of the deep fibular nerve from the neck of the fibula
nerve moves from lateral to anterior compartment of the leg
follows anterior tibial artery
both passes through tibialis anterior and extensor digitoum longus in superior leg, passes between tibialis anterior and extensor hallucis longus in inferior leg
Describe what happens to the deep fibular nerve as it passes the ankle joint
passing anterior to distal tibia at the ankle joint, travelling deep into extensor retinaculum, terminating in the dorsum of the foot - divide into lateral & medial branch
what does the lateral branch of the deep fibular nerve supply?
motor innervation to some of intrinsic muscles of foot
What does the medial branch of the deep fibular nerve supply?
cutaneous branch innervating the skin between the 1st & 2nd toe
What does the deep fibular nerve innervate?
muscles in anterior compartment of the leg:
extensor hallucis longus
extensor digitorum longus
Which actions are the muscles innervated by the deep fibular nerve responsible for?
dorsiflexion of the foot esp. during gait cycle for walking:
1. when a person strikes their heel on the floor in stance phase
2. during swing phase - bring 1 foot forwards
also extensor hallucis brevis & extensor digitorum brevis - extend toes at metatarsophalangeal & interphalangeal joints
Sensory function of the deep fibular nerve
terminates in dorsum of foot as cutaneous nerve
innervates webbed space of skin between great toe (hallux) & 2nd toe
Clinical relevance - footdrop
what causes this?
What are the consequences?
deep fibular nerve becomes entrapped / compressed during its course through the anterior compartment of the leg
causing paralysis of the muscles in the anterior compartment of the leg - patient loses ability to dorsiflex foot - unopposed plantarflexion
How will footdrop affect a patient's gait?
unopposed plantarflexion - giving abnormal gait
1. difficult to clear the ground in the swing phase when walking
2. foot slap on ground as it can't be lowered in controlled manner
What does the patient do to compromise for their footdrop? How will their gait appear?
waddling gait: patient leans excessively onto NORMAL limb
swing-out gait: patient ABducts the ABnormal limb
high stepping gait: the patient flexes the hip and knee excessively on the ABnormal limb - to clear the dropped foot from the floor