Gluteus medius muscle

Gluteus medius
The gluteus medius and nearby muscles
Muscles of the gluteal and posterior femoral regions with origin and insertion of gluteus medius muscle labeled
Latin	musculus gluteus medius
Gray's	subject #128 474
Origin	Gluteal surface of ilium, under gluteus maximus
Insertion	Greater trochanter of the femur
Artery	superior gluteal artery
Nerve	superior gluteal nerve (L4, L5, S1 nerve roots)
Actions	abduction of the hip; preventing adduction of the hip. Medial rotation of thigh.
Antagonist	lateral rotator group

The gluteus medius (or glutæus medius), one of the three gluteal muscles, is a broad, thick, radiating muscle, situated on the outer surface of the pelvis.

Its posterior third is covered by the gluteus maximus, its anterior two-thirds by the gluteal aponeurosis, which separates it from the superficial fascia and integument.

Relations

A bursa separates the tendon of the muscle from the surface of the trochanter over which it glides.

Origin and insertion

The gluteus medius muscle starts, or "originates," on the outer surface of the ilium between the iliac crest and the posterior gluteal line above, and the anterior gluteal line below; the gluteus medius also originates from the gluteal aponeurosis that covers its outer surface.

The fibers of the muscle converge into a strong flattened tendon that inserts on the lateral surface of the greater trochanter. More specifically, the muscle's tendon inserts into an oblique ridge that runs downward and forward on the lateral surface of the greater trochanter.

Action

With the leg in neutral (straightened), the gluteus medius and gluteus minimus function together to pull the thigh away from midline, or "abduct" the thigh. During gait, these two muscles function principally in supporting the body on one leg, in conjunction with the tensor fascia lata, to prevent the pelvis from dropping to the opposite side.

Additionally, with the hip flexed the gluteus medius and minimus externally rotate the thigh. With the hip extended, the gluteus medius and gluteus minimus internally rotate the thigh.^[1]

Dysfunction of the gluteus medius or the superior gluteal nerve can potentially be indicated by a positive Trendelenburg's sign.

Variations

The posterior border may be more or less closely united to the piriformis, or some of the fibers end on its tendon.

The posterior fibres of gluteus medius contract to produce hip extension, lateral rotation and abduction. During gait, the posterior fibres help to decelerate internal rotation of the femur at the end of swing phase.

Additional images

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  Gluteus medius muscle

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  Right hip bone. External surface.

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  Right femur. Posterior surface.

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  Structures surrounding right hip-joint.

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  The arteries of the gluteal and posterior femoral regions.

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  Nerves of the right lower extremity Posterior view.

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  Surface anatomy of the back.

See also

• Trendelenburg gait

References

1. ^ Pratt, N. Clinical Musculoskeletal Anatomy. CBLS: Marietta, OH 2004.

External links

• -200933297 at GPnotebook
• LUC glmd
• SUNY Labs 13:st-0404
• Cross section at UV pelvis/pelvis-e12-15

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.