Anatomy of the legs

Quadriceps

The quadriceps femoris is a group of four muscles located at the front of the thigh. These muscles are:

  1. Rectus Femoris
  2. Vastus Lateralis
  3. Vastus Medialis
  4. Vastus Intermedius

Function: The primary function of the quadriceps is to extend the knee. The rectus femoris also assists with hip flexion due to its origin on the pelvis.

Biomechanics: During knee extension, the quadriceps contract and pull on the patella, which in turn pulls the patellar ligament and extends the knee. The angle of pull from the different muscles ensures a balanced force on the patella and the knee joint.