Gluteal muscles
actions and innervations
| Muscle | Innervation | Action |
|---|---|---|
| Gluteus Maximus | Inferior gluteal nerve | External (lateral) rotation and extension of the hip (thigh/femur) Supports extended knee via iliotibial tract Minimal abduction of thigh |
| Gluteus Medius | Superior gluteal nerve (L5, S1) | Abduction of thigh Medial (internal) rotation of thigh Stabilises pelvis when one leg is raised |
| Gluteus Minimus | Superior gluteal nerve (L5, S1) | Abduction of thigh Medial (internal) rotation of thigh |
| Piriformis | Nerve to piriformis | External (lateral) rotation of thigh Abducts flexed thigh |
origins and insertions
| Muscle | Origin | Insertion |
|---|---|---|
| Gluteus Maximus | Posterior gluteal line of ilium; sacrotuberous ligament, sacrum/coccyx | Gluteal tuberosity of femur |
| Gluteus Medius | External surface of ilium | Greater trochanter |
| Gluteus Minimus | External surface of ilium | Greater trochanter |
| Piriformis |
Trendelenburg sign
- pelvis drops TOWARD side of raised limb
- failure of hip abductors
- Injury/palsy of superior gluteal nerve