When attempting to identify the saphenous nerve on US image, the following anatomical considerations should be kept in mind: (B) US anatomy of the subsartorial space at the midthigh. AMM, adductor magnus muscles GM, gracilis muscle MRN, medial retinacular nerve. The saphenous nerve (SaN) is positioned between the sartorius muscle (SM) and the vastus medialis muscle (VM), anterolateral to the femoral artery (FA) and vein (FV). (A) Cross-sectional anatomy of the saphenous nerve at the level of the thigh. The femoral vein accompanies the artery and saphenous nerve, which all can be identified at a depth of 2–3 cm ( Figure 3).įIGURE 3.

The saphenous nerve is typically imaged by ultrasound as a small, round, hyperechoic structure anterior to the artery. The sides of the triangular canal are formed by the vastus medialis laterally and the adductor longus or magnus medially (depending on how proximal or distal the scan is). The muscle appears as a trapezoid shape beneath the subcutaneous layer of adipose tissue. The sartorius muscle descends in a lateral to the medial direction across the anterior thigh and forms a “roof ” over the adductor canal in the lower half of the thigh. Various approaches to the saphenous nerve block: the perifemoral typically targets the nerve to the vastus medialis muscle with nerve stimulation the subsartorial at the femoral riangle subsartorial at the adductor canal at the medial femoral condyle, between the tendons of the sartorius and the gracilis muscle once the femoral vessels have crossed the adductor hiatus to become the popliteal vessels the paravenous approach using the saphenous vein as a landmark at the level of the tibial tuberosity and at the level of the medial malleolus. The use of ultrasound (US) guidance has improved the success rates of the saphenous nerve blocks compared with field nerve blocks below the knee and blind trans-sartorial approaches.įIGURE 2. Several approaches have been described to nerve block the saphenous nerve along its route from the inguinal area to the medial malleolus ( Figure 2). Typically, a more proximal (mid-thigh) approach and a larger volume of local anesthetic is used for this “adductor canal nerve block”. The nerve block has also been reported as a supplement to multimodal analgesia protocols in patients having knee arthroplasty. A saphenous nerve block is useful as a supplement to sciatic nerve block for foot and ankle procedures that involve the medial aspect of the malleolus and the foot. It also sends infrapatellar branches to the knee joint. It supplies innervation to the medial aspect of the leg down to the ankle and foot. The saphenous nerve is a terminal sensory branch of the femoral nerve. Transducer position and needle insertion to nerve block the saphenous nerve (A) at the level of the lower third of the thigh and (B) below the knee.

Cpt code for ipack block