The main action of muscle "obturator externus muscle" is:
Obturator externus muscle attaches to the external surface of the obturator membrane, adjacent bone, and trochanteric fossa. The obturator externus muscle laterally rotates the femur at the hip joint. The obturator nerve (L3 and L4) innervates this muscle. Ref: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 36. Thigh. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.
Medial rotation of thigh
Lateral rotation of thigh
Flexion of thigh
Extension of thigh