The quadriceps muscles ('quads') dominate the front of the knee, and are the muscles making your 'lap'. If you sit down and put your hands on your lap, then spread your fingers open - all of that muscle under your fingers are the bulky quadriceps.
The arrow in the photograph highlights the vastus lateralis part of the quads bulging out at the side of the thigh.
The drawing on the left is not artistically great (!!) but it shows that the patella exists within the substance of the quadriceps tendon, the fibrous bit at the bottom which attaches to the tibia (shin bone). The proper name for the quads is 'quadriceps femoris'.
'Quadriceps' means '4 heads' - the muscle is actually four separate muscles which work together to straighten (extend) the knee. This detail of the same right knee (illustration on the right) highlights the individual muscles making up the quads: