Common peroneal nerve (common fibular nerve)

Branch of sciatic nerve (L4-S2 ) .( note the different modes of division of the sciatic nerve into tibial and common peroneal nerves )

Course:

• see sciatic nerves
  
  
• The common peroneal nerve [B] skirts laterally in popliteal fossa, medial to biceps femoris tendon.
  
  
• Winds over neck of the fibula, where it divides into superficial and deep branches.

Palpable over lateral condyle of femur, head and neck of fibula

at what points in the common peroneal nerve most likely to be injured ? what are the effects of injury to the common peroneal nerve.

• Muscular to short head of biceps femoris
  
  
• Articular to proximal tibiofibular joint
  
  
• Sural communicating nerve
  
  
• Lateral cutaneous nerve of the calf

a)  The superficial peroneal nerve (S.P.n)

•  Branches off common peroneal at the neck of fibula

•  Descends through the peroneal muscles supplying them

•  Becomes subcutaneous at junction of middle and lower thirds of the leg

•  Its medial and intermediate dorsal cutaneous nerves supplies skin in the lower part of the leg and dorsum of the foot.

•  Each divides into two dorsal digital nerves of the foot to supply the digits except the first interdigital cleft.

b ) deep peroneal nerve

• Arises between the neck of the fibula and peroneus longus
  
  
• Pierces anterior intermuscular septum and extensor digitorum longus and descends in the anterior compartment of the leg with anterior tibial vessels.
  
  
• Runs on the interosseus membrane between tibialis anterior and extensor digitorum longus.
  
  
• Lower down near the ankle it is crossed by superficially by extensor hallucis.
  
  
• At the ankle it lies between FHL and FDL

Medial branch to first interdigital cleft

Lateral branch to extensor digitorum brevis

Muscular: to extensors, dorsiflexors of the ankle
Articular: ankle joint
Cutaneous: 1 st interdigital cleft
Injury: causes foot drop