Gluteus minimus muscle

The gluteus minimus (or glutæus minimus), the smallest of the three gluteal muscles, is situated immediately beneath the gluteus medius.

Origin and insertion

It is fan-shaped, arising from the outer surface of the ilium, between the anterior and inferior gluteal lines, and behind, from the margin of the greater sciatic notch.

The fibers converge to the deep surface of a radiated aponeurosis, and this ends in a tendon which is inserted into an impression on the anterior border of the greater trochanter, and gives an expansion to the capsule of the hip joint. It is also a local stabilizer for the hip.

Relations

A bursa is interposed between the tendon and the greater trochanter.

Between the gluteus medius and gluteus minimus are the deep branches of the superior gluteal vessels and the superior gluteal nerve.

The deep surface of the gluteus minimus is in relation with the reflected tendon of the rectus femoris and the capsule of the hip joint.

Action

The gluteus medius and gluteus minimus abduct the thigh, when the limb is extended, and are principally called into action in supporting the body on one limb, in conjunction with the Tensor fasciæ latæ.

Gluteus minimus (fossil)

Gluteus minimus is a fossil from the Upper Devonian of Iowa. It was first collected in 1902, but only described in 1975. Each animal appears as a bi-lobed lens up to 11 mm × 8 mm (0.43 in × 0.31 in), and almost all specimens share the same slight asymmetry. The species is of uncertain affinities, having been thought of as either a fish tooth or a brachiopod.

Collection history

Specimens of G. minimus were first collected by Stuart Weller in 1902, from the Maple Mill Shale near Maple Mill on the English River, Washington County, Iowa. The Upper Devonian Maple Mill Shale appears as a series of shale lenses which are rich in fossils, including conodonts, fish remains, possible sporocarps, gastropods, brachiopods, bivalves and scolecodonts.

At a similar time to Weller's collections, Charles Rochester Eastman collected specimens from the Kinderhook Beds at Burlington, Des Moines County, Iowa. C. H. Belanski collected specimens thirty years later from the Lime Creek Formation in Floyd County, Iowa. Thousands of specimens have since been collected from the Maple Mill Shale and nearby sites, and two have been found in a well at Columbus City, Louisa County, Iowa.