The common peroneal nerve (P) typically presents as one single round anehoic (black) profile just before it branches off from the sciatic nerve (S)

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– Place the patient in the lateral position and the probe in the popliteal crease

– Visualise the tibial nerve between the popliteal artery and the probe

– Track the tibial nerve proximally until it unites with the peroneal nerve and the two become the sciatic nerve

– Insert the needle from the lateral end of the probe and advance the needle in-plane until the tip of the needle touches the peroneal nerve tangentially

– Inject the local anesthetic

– Relocate the tip of the needle until you obtain complete perineural spread of local anaesthetic around both the peroneal and the tibial nerve

The sciatic nerve branches (the tibial nerve and the common peroneal nerve) innervate the entire leg, ankle and foot

The only exception is the saphenous nerve territory and a strip of skin distal to the popliteal fossa which is innervated by the posterior femoral cutaneous nerve

– Locate the pulsating popliteal artery at the level of the popliteal crease

– Look for the tibial nerve between the artery and the skin

– Look for the common peroneal nerve lateral to the tibial nerve

– Track the tibial nerve and the common peroneal nerve proximally until they unite and become the sciatic nerve

The deep peroneal nerve supplies the skin of the cleft between the 1st and 2nd toes

The deep peroneal nerve is the biggest of the two terminal branches of the common peroneal nerve

The deep peroneal nerve descends within the anterior crural compartment and supplies all the muscles of this compartment

It crosses in front of the ankle joint, giving an articular branch to the ankle joint, before the terminal branches innervate the dorsum of the foot, lateral to the dorsalis pedis artery

It innervates the skin of the interspace between the 1st and 2nd toes

It also innervates the digital extensor muscles and some of the tarsal and tarsometatarsal joints

The superficial fibular nerve emerges through the fibular musculature about halfway down the leg

It innervates the dorsum of the foot and the toes – except the interspace between the first and the second toe

The lateral cutaneous nerve of calf (also known as the lateral sural nerve) is a cutaneous branch of the common fibular nerve

It arises near the neck of the fibula and supplies skin over the lateral aspect of the leg just distal to the knee

The superficial fibular nerve is the smallest of the two terminal branches of the common fibular nerve

It innervates the muscles of the lateral compartment of the leg

It supplies cutaneous branches to the lateral aspect of the distal half of leg

The branches of the superficial peroneal nerve supply the dorsum of the foot and the toes

The common peroneal nerve is the lateral of the two terminal branches of the sciatic nerve

From its origin in the popliteal fossa it descends infero-laterally just medial to the tendon of biceps femoris. It winds around the fibular neck and divides into its two terminal branches: The superficial peroneal nerve and the deep peroneal nerve

In the knee region, the common peroneal nerve gives the following branches before dividing into its terminal branches:

– Articular branches: The lateral genicular nerves
– The peroneal communicating nerve which joins the sural nerve from the tibial nerve
– The lateral cutaneous nerve of calf which arises within the popliteal fossa and supplies the skin over the upper part of the lateral part of the leg