The largest muscle in the body is gluteus maximus. The gluteus maximus is the largest and most superficial of the three gluteal muscles (The gluteal muscles are the three muscles that make up the human buttocks. The gluteal muscles are formed of the gluteus maximus, gluteus minimus and gluteus medius). It is considered a part of the thigh muscle group. It makes up a large portion of the shape and appearance of the buttocks.lt is a broad and thick fleshy mass of a quadrilateral shape, and forms the prominence of the nates. Stapedius is the smallest muscle in the body, located in the middle ear. Contraction of the stapedius pulls the stapes, altering the mechanical efficiency of the ossicular chain. Quadriceps refers to the muscles on the anterior portion of the thigh which extends the knee. The quadriceps femoris, commonly the ‘quadriceps’, is a large muscle in the thigh, composed of the sections rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis. The gastrocnemius muscle is a powerful superficial muscle that is in the back part of the lower leg (the calf).