Injury to long thoracic nerve. It can be tested by asking the patient: (A) Resistance against wall, (B) Raise the arm above head, (C) Touch opposite shoulder, (D) Lift a heavy object.
Answer is A. Long thoracic nerve supplies the serratus anterior muscle, which helps in overhead abduction of shoulder, pushing and punching movements. So it can be tested by asking the patient for forward pressure with the hands against a wall, or against resistance offered by the examiner. B D Chaurasia 7th edition Page no : 46,47