Lower limb
Gluteus maximus
Musculus gluteus maximus
- Origin
- Ilium posterior to the posterior gluteal line, the sacrum, the coccyx and the sacrotuberous ligament
- Insertion
- Iliotibial tract and the gluteal tuberosity of the femur
- Function
- Extension and external rotation of the hip; important in standing up, climbing stairs and sprinting
- Innervation
- Inferior gluteal nerve, L5-S2
- Movement & chain
- Provides the main power source for explosive hip extension (rising from a squat, sprint start) and stabilizes the knee in extension via the iliotibial tract.
- Palpation
- Readily palpable across the entire buttock contour, especially during contraction against resistance in hip extension (for example in prone position).
- Clinical
- Weakness produces compensatory hyperlordosis of the lumbar spine and reduced push-off strength; atrophy occurs with prolonged inactivity.
- Segmental innervation
- L5-S2, tested with resisted hip extension.
- In clinical practice
- The upper outer quadrant of the buttock (above the line between the posterior superior iliac spine and the greater trochanter) is the classic site for intramuscular injections, to avoid the sciatic nerve.
- Region in the model
- Lower limb