US Guided Regional Anesthesia

7 – The medial calcaneal nerve branch of the tibial nerve

The medial calcaneal nerve is a branch of the tibial nerve

It arises postero-inferior to the medial malleolus

The medial calcaneal nerve branches innervates the skin of the heel

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The green colour depicts the medial calcaneal nerve branch of the tibial nerve

6 – The lateral plantar nerve branch of the tibial nerve

The lateral plantar nerve descends postero-inferior to the medial malleolus

It supplies some of the flexor muscles of the foot besides giving cutaneous branches to the lateral side of the sole of the foot

Branches from the lateral plantar nerve cross over to the dorsum of the toes to supply the nail bed

The lateral plantar nerve also contributes to the sensory innervation of some of the the tarsal and metatarsal joints

The lateral plantar nerve in the foot is analogous to the ulnar nerve in the hand

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The green colour depicts the lateral plantar nerve branch of the tibial nerve

5 – The medial plantar nerve branch of the tibial nerve

The medial plantar nerve descends postero-inferior to the medial malleolus

It innervates the skin over the medial aspect of the sole of the foot

The nerve branches cross over to the dorsum of the toes to supply the nail beds

The medial plantar nerve distribute sensory branches to the tarsal and metatarsal joints

The medial plantar nerve supplies some of the flexor muscles of the foot

The medial plantar nerve of foot is analogous to the median nerve in the hand

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The green colour depicts the medial plantar nerve branch of the tibial nerve

4 – Tibial nerve branches to the knee: The genicular nerves

Within the popliteal fossa the tibial nerve branches off the medial genicular nerves

The lateral branches come from the peroneal nerve

The genicular nerves are sensory nerves that supply the capsule and ligaments of the knee joint

A popliteal sciatic nerve block proximal to the sciatic nerve bifurcation blocks the genicular nerves branching off the tibial nerve. I.e. the tibial innervation of the knee is blocked by a popliteal sciatic nerve block

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The green colour depicts the genicular nerves which branch off from the tibial nerve (to the left) and the common peroneal (to the right) and innervate the knee

2 – Anatomy of the sciatic nerve in the popliteal fossa

In the popliteal fossa the sciatic nerve splits in two branches: the tibial nerve medially and the common peroneal nerve laterally

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The popliteal fossa contains the tibial nerve (TN) medially and the common peroneal nerve (PN) laterally
ST = semitendinosus muscle; SM = semimembranosus muscle; BF = biceps femoris muscle

3 – The tibial nerve

The tibial nerve runs in the posterior compartment of the leg, before it divides into the two terminal branches: the medial and the lateral plantar nerves. The two terminal branches give off cutaneous and muscular branches to the foot

Within the popliteal fossa, the tibial nerve gives off:
– articular branches to the knee joint (the genicular nerves)
– muscular branches to the ankle flexor muscles in the posterior compartment
– a cutaneous nerve to the lateral ankle and foot – the sural nerve

In the distal part of the leg, the tibial nerve gives off:
– articular branches to the ankle joint
– a cutaneous nerve to the heel, the medial calcaneal nerve

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The green colour depicts the tibial nerve in posterior compartment of the leg

1 – Anatomy of the sciatic nerve

The sciatic nerve emerges from the pelvis through the greater sciatic foramen underneath the piriformis muscle

It descends in the midline of the thigh between the greater trochanter and the ischial tuberosity

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The yellow sciatic nerve (SN) emerges from the lower border of the triangular piriformis muscle

13 – The saphenous nerve can be blocked separately

The saphenous nerve is the biggest branch from the femoral nerve

The saphenous nerve runs in the thigh in the femoral triangle and the adductor canal alongside the femoral vessels. In the femoral triangle and the upper part of the adductor canal the saphenous nerve is lateral to the vessels

The saphenous nerve is 100% sensitive innervating the medial part of the knee capsule, the skin and subcutaneous tissue antero-inferior to the knee, of the medial leg, the medial ankle joint and the subtalar joints

Indications: For surgical anaesthesia or pain management of the leg you should combine a sciatic and a saphenous nerve block

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The figure shows the green saphenous nerve running alongside and lateral to the femoral artery in the femoral triangle

17 – Blocking the saphenous nerve separately in the adductor canal

Position: place the patient supine, rotate the thigh external

Probe: select a linear, high-frequency transducer

Place/Plane: place the transducer mid-thigh medially and perpendicular to the adductor canal

First locate the pulsatile femoral artery

You may track the artery from the inguinal ligament until it dives under the sartorius muscle

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The in-plane approach to block the saphenous nerve at the midthigh level in the femoral triangle