Chapter 145. Saphenous Nerve Blocks

Anatomy (Figure 145-2):

The saphenous nerve is a purely sensory branch of the femoral nerve. It emerges in the inguinal area, travels in the femoral canal, deep to the sartorius muscle, along with the femoral artery and vein and the nerve to the vastus medialis (NVM), which gives branches along the way in the thigh. The saphenous nerve gives off some articular branches to the knee joint. In the lower leg, while traveling in proximity to the greater saphenous vein, it innervates the skin of the anteromedial aspect of the lower leg.

Techniques have been described to block the saphenous nerve at every level along its route (Figure 145-3):

• In the inguinal area (perifemoral)
• In the femoral canal (using a subsartorial or transsartorial approach)
• At the medial femoral condyle
• As a field block below the knee, from the anterior tibial tuberosity to the anterosuperior edge of the muscle belly of the gastrocnemius (Figure 145-4)
• In the lower leg (paravenous approach)
• At the ankle, anterior to the medial malleolus

Indications:

Anesthesia or analgesia of the medial aspect of the lower leg or the ankle, in combination with a popliteal sciatic block, for surgery of the lower leg, the ankle, or the foot.

Contraindications:

None specific.

Technique using NS (in the inguinal area):

• Patient positioned supine; locate femoral ...