saphenous nerve /səfē″nəs/ [Gk, saphenes, manifest; L, nervus, nerve] , the largest and longest superficial branch of the femoral nerve, supplying the skin of the medial side of the leg and the skin over the patella. On the lateral side of the knee it joins branches of the lateral femoral cutaneous nerve to form the patellar plexus. One branch of the saphenous nerve below the knee supplies the ankle. Another branch below the knee supplies the medial side of the foot. See also femoral nerve.