The Femoral And Sciatic Nerves
Place the active recording electrode over the vastus medialis muscle and the reference electrode on the patella.
Stimulate the nerve in the groin over the femoral triangle or at Hunter’s canal. You can also stimulate it above the inguinal ligament.
Because this nerve is difficult to stimulate in obese patients, especially above the inguinal ligament, needle electrodes may be used for that purpose.
The posterior tibial nerve may be involved as part of a sciatic nerve injury; at the popliteal fossa; in the tarsal tunnel following ankle injury; and rarely at an anterior opening of the abductor hallucis muscle.
Place the recording electrodes on those muscles used in peroneal or posterior tibial testing. The stimulating electrode must be a needle electrode over the sciatic notch, which is halfway between the ischial tuberosity and greater trochanter.
The sciatic nerve may be injured high along its course at the roots and plexus level; underneath the pyriformis muscle; in the buttock (most notoriously by injury from intramuscular injections); and along its entire course in the thigh by fracture, missile wounds orother types of injuries.