The main action of muscle "obturator externus muscle" is:: (A) Medial rotation of thigh, (B) Lateral rotation of thigh, (C) Flexion of thigh, (D) Extension of thigh
Answer is B. 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.