25: Peroneal/Fibular Neuropathy

Question 1

What innervates the lateral knee with regards to sensation?

Answer 1

Lateral cutaneous nerve of the knee (if involved would suggest lesion proximal to the fibular head/neck)

Question 2

What percent drop in fibular CMAP amplitude suggests focal conduction block?

Answer 2

20%

Question 3

Why would deep fibular fibers be more affected than superficial?

Answer 3

Could be selective fascicular vulnerability of the deep fibers lying closest to the fibula and are prone to compression

Question 4

What nerve does the lateral sural cutaneous nerve arise from?

Answer 4

Common fibular nerve

Question 5

Where do the extraneural ganglion cysts impinging on the fibular nerve arise from?

Answer 5

Superior tibiofibular joint

Question 6

With regards to prognosis, what is worse for recovery when these ultrasound findings are seen?

Answer 6

Greater enlargement of nerves, and longer lengths of abnormal nerve

Question 7

What does the deep fibular nerve innervate?

Answer 7

TA, EDL, EHL, peroneus tertius, EDB