(Anatomy)any of several straight muscles, in particular (剖)直肌,尤指 ■(亦作 rectus abdominis abˈdɒmɪnɪs)each of a pair of long flat muscles at the front of the abdomen, joining the sternum to the pubis and acting to bend the whole body forwards or sideways 腹部直肌 ■any of a number of muscles controlling the movement of the eyeball 眼部直肌