|Derivation||The medium-sized (medius) muscle of the buttock (gluteus). (Gluteus minimus, the smallest of the three including maximus, lies under medius.)|
|Origin||A wide area on the lateral surface of the ilium.|
|Insertion||The great trochanter of the femur.|
|Action||Lifts the thigh to the side. Its anterior and posterior portions rotate it medially and laterally respectively.|
Because of its position, gluteus medius is visible on nearly any view of the trunk. (Compare with external oblique, c.f., which shares this trait.) On the dorsal view, it appears as a more-or-less spherical form above and lateral to gluteus maximus, which covers its posterior portion.
On the lateral view, it forms most of the bulk between the pelvic crest and the great trochanter. Gluteus medius can be used to locate the great trochanter, an important skeletal landmark close to the skin (as a tap on this point will attest).
When lifting the leg to the side, the anterior portion of this muscle forms a distinct bulk that looks not unlike tensor fascia lata. It should be remembered that gluteus medius inserts at the great trochanter, while the tensor drops in front and below.
On the view from the front, gluteus medius appears as a curve that passes in back of both external oblique and the tensor fascia lata.