|Derivation||The straight (rectus) muscle on the femur (femoris).|
|Origin||Anterior inferior iliac spine of the pelvis.|
|Action||Straightens the leg at the knee, and bends it at the hip.|
Rectus femoris is the only quadriceps muscle that originates on the the pelvis, which is why it can bend the leg at two joints.
As mentioned earlier, it fills the almond-shaped space between the teardrop-shaped vastus medialis and lateralis. On its upper end there is a furrow in the center of the muscle that is sometimes visible on the surface.