Rectus femoris is the name of a muscle that is located in the front part of the thigh in humans. However, as with other terms in medicine and anatomy, there are other synonyms that can be used to refer to this muscle. One of the synonyms for rectus femoris is the straight thigh muscle, which describes the muscle's shape and function accurately. Another synonym is the quadriceps femoris muscle, which is a group of four muscles including rectus femoris that work together to move the leg and knee. Other synonyms for rectus femoris include the thigh extensor muscle, quadriceps extensor, and the anterior thigh muscle. Regardless of the synonym used, rectus femoris is an important muscle that is responsible for various functions in the human body.