Gluteus maximus muscle

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Gluteus maximus

The gluteus medius and nearby muscles

Structures surrounding right hip-joint. (Gluteus maximus visible at bottom.)
Gray's	subject #128 474
Origin:	Gluteal surface of ilium, lumbar fascia, sacrum, sacrotuberous ligament
Insertion:	Gluteal tuberosity of the femur, iliotibial tract
Blood:	superior and inferior gluteal arteries
Nerve:	inferior gluteal nerve (L5, S1, S2 nerve roots)
Action:	external rotation and extension of the hip joint, supports the extended knee through the iliotibial tract, chief antigravity muscle in sitting.

The gluteus maximus is the largest and most superficial of the three gluteal muscles. In Gray's Anatomy, it is considered a part of the thigh muscle group. It makes up a large portion of the shape and appearance of the buttocks.

It is a broad and thick fleshy mass of a quadrilateral shape, and forms the prominence of the nates.

Its large size is one of the most characteristic features of the muscular system in humans, connected as it is with the power he has of maintaining the trunk in the erect posture.

The muscle is remarkably coarse in structure, being made up of fasciculi lying parallel with one another and collected together into large bundles separated by fibrous septa.

1 Origin and insertion
2 Bursae
3 Actions
4 Additional images
5 External links

[edit] Origin and insertion

It arises from the posterior gluteal line of the ilium, and the rough portion of bone including the crest, immediately above and behind it; from the posterior surface of the lower part of the sacrum and the side of the coccyx; from the aponeurosis of the sacrospinalis, the sacrotuberous ligament, and the fascia (gluteal aponeurosis) covering the gluteus medius.

The fibers are directed obliquely downward and lateralward;

those forming the upper and larger portion of the muscle, together with the superficial fibers of the lower portion, end in a thick tendinous lamina, which passes across the greater trochanter, and is inserted into the iliotibial band of the fascia lata;
the deeper fibers of the lower portion of the muscle are inserted into the gluteal tuberosity between the vastus lateralis and adductor magnus.

[edit] Bursae

Three bursae are usually found in relation with the deep surface of this muscle:

One of these, of large size, and generally multilocular, separates it from the greater trochanter;
a second, often wanting, is situated on the tuberosity of the ischium;
a third is found between the tendon of the muscle and that of the vastus lateralis.

[edit] Actions

When the Gluteus maximus takes its fixed point from the pelvis, it extends the femur 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 especially 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, Semitendinosus, and Semimembranosus.

The Glutæus 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.

The lower part of the muscle also acts as an adductor and external rotator of the limb.

[edit] Additional images

Muscles of male perineum.

The arteries of the gluteal and posterior femoral regions.

Surface anatomy of the back.

Back of left lower extremity.

[edit] External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.