17. 鎖骨下動脈(subclavian artery )與腋動脈( axillary artery)通常以何構造為分界? (A) 第一肋骨(rib) (B) 大圓肌(teres major muscle ) (C) 小圓肌(teres minor muscle ) (D) 胸小肌(pectoralis minor muscle )