The saphenous nerve is a terminal cutaneous branch of the femoral nerve. It is commonly blocked to complement anesthesia of the lower leg. It is strictly a sensory nerve; it has no motor component. The saphenous innervates the skin over the medial, anteromedial, and posteromedial aspect of the lower leg from knee to ankle. (See picture)
The saphenous nerve is most often injured during vein harvest for CABG because it runs with the saphenous vein, or by trochanter placement during knee arthroscopy.
The sign of saphenous nerve damage is loss of sensation over the medial aspect of the lower leg.
The nerve can be blocked just above the medial malleolus, at the level of the tibial tuberosity, or using a transsartorial approach