Transverse sonogram of the femoral nerve and needle direction during the in-plane three-step needle insertion technique. Arrow 1 corresponds to the first step in which the Tuohy needle is inserted in order to penetrate the fascia iliaca at the lateral part of the femoral nerve. Step 2, indicated by arrow 2, involves the needle tip being pulled back in order to decrease the angle of the needle shaft. Arrow 3 shows the third step of the technique, in which the needle is inserted into the space between the fascia iliaca and the femoral nerve. FA: femoral artery, FI: fascia iliaca, FN: femoral nerve.