the quadriceps muscle is consist of four muscle 1. -rectus femoris -vastus intermedius -vastus medialis -vastus lateralis These four large anterior thigh muscles insert below the knee and act to extend the knee joint. the three vast lie deep to the rectus femoris and two have their origins on the posterior femur. the rectus femoris originates on the pelvis and thereby can act to flex the hip. 1.rectus femoris Origin -long head: anterior inferior iliac spine short head: upper margin of the acetabulum Insertion -patella and via patellar ligament to tibial tuberosity Nerve supply -femoral nerve (l2,3,4) Blood supply -lateral femoral circumflex artery Action -Extention of knee assist flexion of femur at hip The palpation-anterior surface of the thigh during active knee extension The Rectus femoris is the only muscle in the quadriceps group that crosses both the hip and knee joints. its combined action is seen as the leg is brought