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quadriceps femoris(commonly known as quads) muscle group on the front of the thigh comprising lateral, intermediate and medial vasti (all contributing to knee extension, with origin from the shaft of the femur) and rectus femoris (contributing also to hip flexion, by its origin from the ilium of the pelvis). Parts of the vasti are inserted into the top and sides of the patella, and contribute tendinous reinforcements to the joint capsule of the knee. The four muscles converge onto the single quadriceps tendon which spans the front of the knee to be inserted as the patellar tendon (ligament) into the tibial tubercle (tuberosity). See also patella, Q(quadriceps)-angle.
rectus femoristwo-headed (straight and reflected) muscle within quadriceps femoris group; lies between iliopsoas and tensor fascia lata superiorly and vastus lateralis and medialis inferiorly, and overlying vastus intermedius
origin straight head from anterior inferior iliac spine; reflected head from acetabulum area
insertion common patellar tendon, with vasti tendons
nerve supply femoral nerve
action knee extension and hip flexion