The anatomy of the quadriceps muscles are a group of four (4) muscles that sits on the front aspect or the anterior of the thigh muscle.

The four muscle are called the Vastus Medialis, Intermedius, Lateralis, and the Rectus Femoris. These quad muscles are attached to the front of the tibia and it also originates at the top of the femur.

However, the exception to this rule is the Rectus Femoris which actually crosses the hip joint and originates on the pelvis.

The function of this muscle has the purpose to extend the knee or (straighten out the knee).

The Rectus Femoris functions to extend the knee, but also acts as a hip flexor because it crosses the hip joint.