Fig. 1

The pelvic and femoral bone models with the hip abductor and adductor muscle lines of action, viewing from the front (a), lateral (b), and oblique (c). The gluteus medius and minimus are divided into anterior, middle, and posterior bundles. The adductor magnus is divided into anterior and posterior bundles. All the muscles are listed as follows: gluteus medius anterior bundle (1, GMDA), gluteus medius median bundle (2, GMDM), gluteus medius posterior bundle (3, GMDP), gluteus minimus anterior bundle (4, GMIA), gluteus minimus median bundle (5, GMIM), gluteus minimus posterior bundle (6, GMIP), piriformis (7, PF), adductor magnus anterior bundle (8, AMA), adductor magnus posterior bundle (9, AMP), adductor longus (10, AL), adductor brevis (11, AB), and pectineus (12, PT)