The quadriceps femoris consists of four large muscles in the front of the thigh: the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.

A person with a quadriceps muscle strain has stretching or tearing of the muscles in the front of the thigh. A quadriceps muscle strain is caused by an injury. Most quadriceps strains are partial tears of the muscle. Severe quadriceps injuries may cause a complete tear, called a quadriceps rupture.