The gluteus medius is a broad, fan-shaped muscle on the outer surface of the pelvis, partially covered by the gluteus maximus, that is primarily responsible for abducting the hip and, more importantly, preventing the pelvis from dropping to the opposite side when standing on one leg. This pelvic stabilisation role during walking and running makes it one of the most clinically relevant muscles in the lower limb, as weakness produces the characteristic Trendelenburg gait pattern and contributes to a wide range of lower extremity injuries.
| Origin | Outer surface of the ilium between the posterior and anterior gluteal lines |
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| Insertion | Lateral surface of the greater trochanter of the femur |
| Nerve Supply | Superior gluteal nerve (L4, L5, S1) |
| Blood Supply | Superior gluteal artery |
| Actions | Abduction of the hip, the primary action; Anterior fibres: internal rotation and flexion of the hip; Posterior fibres: external rotation and extension of the hip; Stabilises the pelvis against contralateral drop during single-leg stance (Trendelenburg stabilisation) |
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During single-leg stance, the gluteus medius contracts to maintain the pelvis level against the pull of gravity, a role that is tested directly by the Trendelenburg sign, and weakness forces compensatory lateral trunk lean toward the weak side to reduce the demand on the muscle.
Gluteus medius weakness is one of the most consistent findings associated with iliotibial band syndrome, patellofemoral pain, hip osteoarthritis, and low back pain, making it a target in rehabilitation for a remarkably diverse range of complaints. Trochanteric bursitis, inflammation of the bursa overlying the greater trochanter, frequently co-presents with gluteus medius tendinopathy, the latter being the more common primary diagnosis in lateral hip pain in middle-aged women. Assessment involves the single-leg squat, where a dropping of the contralateral pelvis or ipsilateral trunk lean indicates insufficient medius strength.
The gluteus medius is palpable just lateral to the iliac crest and above the greater trochanter during resisted hip abduction, it firms noticeably under the fingertips. The distal tendon can be felt attaching to the lateral facet of the greater trochanter, often tender in cases of gluteus medius tendinopathy.
Degenerative changes in the gluteus medius tendon at its greater trochanteric attachment, producing lateral hip pain that worsens with prolonged walking, single-leg activities, and lying on the affected side, the most common cause of 'greater trochanteric pain syndrome' in middle-aged women.
A partial or complete avulsion of the gluteus medius tendon from the greater trochanter, presenting like a rotator cuff tear at the shoulder with significant abductor weakness and a positive Trendelenburg sign, often requiring surgical repair in active individuals.
