The gluteus medius, one of the three

gluteal muscles The gluteal muscles, often called glutes are a group of three muscles which make up the gluteal region commonly known as the buttocks: the gluteus maximus, gluteus medius and gluteus minimus. The three muscles originate from the ilium and sa ...

, is a broad, thick, radiating muscle. It is 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 The gluteal aponeurosis is a fibrous membrane, from the fascia lata, that lies between the iliac crest and the superior border of the gluteus maximus The gluteus maximus is the main extensor muscle of the hip. It is the largest and outermost o ...

, which separates it from the superficial fascia and integument.

Structure

The gluteus medius muscle starts, or "originates", on the outer surface of the ilium between the

iliac crest The crest of the ilium (or iliac crest) is the superior border of the wing of ilium and the superiolateral margin of the greater pelvis. Structure The iliac crest stretches posteriorly from the anterior superior iliac spine (ASIS) to the poster ...

and the

posterior gluteal line The gluteal lines are three curved lines outlined from three bony ridges on the exterior surface of the ilium in the gluteal region. They are the anterior gluteal line; the inferior gluteal line, and the posterior gluteal line. The gluteus mini ...

above, and the anterior gluteal line below; the gluteus medius also originates from the

that covers its outer surface. The fibers of the muscle converge into a strong flattened

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

that inserts on the lateral surface of the

greater trochanter The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system. It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Stan ...

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

Relations

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

Variations

The posterior border may be more or less closely united to the

piriformis The piriformis muscle () is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group. The piriformis muscle has its origin upon the front surface of the sacrum, and in ...

, 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.

Function

* The anterior part acting alone helps to flex and internally rotate the hip. * The posterior part acting alone helps to extend and externally rotate the hip. * The anterior and posterior parts working together abduct the hip and stabilize the pelvis in the coronal plane.Schünke, M., Schulte, E., Schumacher, U., Ross, L. M., & Lamperti, E. D. (2006). Thieme atlas of anatomy. Stuttgart: Thieme. page 424

Clinical significance

Dysfunction of the gluteus medius or the superior gluteal nerve can potentially be indicated by a positive

Trendelenburg's sign Trendelenburg's sign is found in people with weak or paralyzed abductor muscles of the hip, namely gluteus medius and gluteus minimus. It is named after the German surgeon Friedrich Trendelenburg. It is often incorrectly referenced as the Tr ...

Additional images

File:Gluteus medius muscle - animation04.gif, Position of gluteus medius muscle (shown in red).

Hip bone The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the ilium, isch ...

is shown in semi-transparent. File:Gray344.png, Structures surrounding right hip-joint. File:Slide2hh.JPG, Gluteus medius muscle (shown in green text)

References

External links

* * {{DEFAULTSORT:Gluteus Medius Muscle Hip abductors Hip lateral rotators Hip medial rotators Muscles of the gluteus Hip muscles Muscles of the lower limb