Keeping the arm as stiff as a board, swing it in an arc-like motion from the shoulder, making contact in front of the shoulder.
臂要伸直，并保持伸直的姿式不变，以肩为轴把球拍划出弧线，在肩部的前方勾击来球。
2
Results 15 cases presented crescent-like watery density under the skull, 8 cases presented arc-like watery density beside cerebral falx, while the remaining 5 cases presented both.