Musculus gluteus maximus

The gluteus maximus (also known collectively with the gluteus medius and minimus, as the gluteal muscles, and sometimes referred to informally as the 'glutes') is the main extensor muscle of the hip. It is the largest and most superficial of the three gluteal muscles and makes up a large portion of the shape and appearance of each side of the hips. Its thick fleshy mass, in a quadrilateral shape, forms the prominence of the buttocks.The gluteus maximus as it appear on a skeleton without other musclesAll gluteal muscles, maximus in yellowStructures surrounding right hip-joint (gluteus maximus visible at bottom)Innervation and blood-supply of the gluteus maximus.Gluteus maximus cut showing underlying structures.Gluteus maximus cut showing underlying structures.Structures visible under the gluteus maximus.Innervation as seen from under the gluteus maximus.The gluteus medius and nearby muscles. The gluteus maximus (also known collectively with the gluteus medius and minimus, as the gluteal muscles, and sometimes referred to informally as the 'glutes') is the main extensor muscle of the hip. It is the largest and most superficial of the three gluteal muscles and makes up a large portion of the shape and appearance of each side of the hips. Its thick fleshy mass, in a quadrilateral shape, forms the prominence of the buttocks. Its large size is one of the most characteristic features of the muscular system in humans, connected as it is with the power of maintaining the trunk in the erect posture. Other primates have much flatter hips and can not sustain standing erectly. The muscle is remarkably coarse in function and structure, being made up of muscle fascicles lying parallel with one another, and collected together into larger bundles separated by fibrous septa. It arises from the posterior gluteal line of the inner upper ilium, a pelvic bone, and roughly the portion of the bone including the crest of the ilium (the hip bone), immediately above and behind it; and from the posterior surface of the lower part of the sacrum, the base of the spine, and the side of the coccyx, the tailbone; from the aponeurosis of the erector spinae (lumbodorsal fascia), the sacrotuberous ligament, and the fascia covering the gluteus medius (gluteal aponeurosis).The fibers are directed obliquely downward and lateralward;The gluteus maximus has two insertions: Three bursae are usually found in relation with the deep surface of this muscle: When the gluteus maximus takes its fixed point from the pelvis, it extends the acetabulofemoral joint and brings the bent thigh into a line with the body. Taking its fixed point from below, it acts upon the pelvis, supporting it and the trunk upon the head of the femur; this is particularly obvious in standing on one leg. Its most powerful action is to cause the body to regain the erect position after stooping, by drawing the pelvis backward, being assisted in this action by the biceps femoris (long head), semitendinosus, semimembranosus, and adductor magnus. The gluteus maximus is a tensor of the fascia lata, and by its connection with the iliotibial band steadies the femur on the articular surfaces of the tibia during standing, when the extensor muscles are relaxed.