re.trac.tor
n.（名词）One that retracts, as:缩回的东西，如：Anatomy A muscle, such as a flexor, that retracts an organ or a part.【解剖学】 牵拉肌：能使器官或部位收缩的肌肉，例如屈肌Medicine A surgical instrument used to hold back organs or the edges of an incision.【医学】 牵开器：一种手术仪器，用于将器官或切开的边缘撑住
