The muscle that stops the pelvis from dropping on the unsupported side when you stand on one leg
Gluteus medius — with gluteus minimus.
Anatomy · Muscles
Gluteus medius
Abductor that keeps the pelvis level
Lower limb · gluteal region
Gluteus medius is a fan-shaped muscle on the outer surface of the ilium, lying deep to gluteus maximus in its posterior part and forming the upper outer buttock. It inserts on the greater trochanter of the femur and abducts the thigh; more importantly, it holds the pelvis level when standing on one leg. It is supplied by the superior gluteal nerve.
How to spot them
- ▸Fan-shaped muscle on the outer surface of the ilium, partly covered by gluteus maximus
- ▸Fibres converge to a strong tendon on the lateral side of the greater trochanter
- ▸Lies over gluteus minimus, the smallest gluteal muscle
- ▸Site of the classic dip of the pelvis when it fails, the Trendelenburg sign
What to know
A positive Trendelenburg sign, the pelvis sagging on the side opposite the leg you stand on, indicates weakness of this muscle
Gluteus medius — or damage to the superior gluteal nerve.
It arises from the outer ilium between the anterior and posterior gluteal lines and inserts on the greater trochanter
Gluteus medius.
A muscle supplied by the superior gluteal nerve (L4–S1), which passes above piriformis
Gluteus medius.
Its anterior fibres also medially rotate the thigh, while the whole muscle abducts it
Gluteus medius.
Its fibres converge from a broad fan on the ilium to a tendon that passes over a bursa on the greater trochanter
Gluteus medius.
Key ideas
- In walking, gluteus medius and minimus on the stance side stop the pelvis tipping down on the swing side.
- Gluteus minimus lies deep to it and shares its actions; together they are the hip abductors.
Quick-fire facts
- •Origin: outer surface of the ilium between the anterior and posterior gluteal lines.
- •Insertion: lateral surface of the greater trochanter of the femur.
- •Nerve supply: superior gluteal nerve (L4–S1).
- •Actions: abducts the thigh; anterior fibres medially rotate; stabilises the pelvis in single-leg stance.
- •Lies deep to gluteus maximus (posteriorly) and superficial to gluteus minimus.
- •Weakness gives the Trendelenburg sign or gait.
- •The superior gluteal nerve and vessels emerge above piriformis, between gluteus medius and minimus.
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Sources
- TeachMeAnatomy — Gluteus medius - attachments, actions, innervation
- TeachMeAnatomy — Gluteus maximus - attachments, actions, innervation