Generally, the first assistant is the attending physician. He can independently complete some minor operations such as appendectomy, hernia repair, etc. In the future, he can perform the surgery after being promoted to director. The second assistant is a practicing physician who can cooperate with the director. Or the first assistant can complete some medium-level surgeries, the third assistant is a practicing assistant physician who cannot complete all surgeries independently, so it depends on the degree of his professional title promotion and skill improvement, and the fourth assistant is an instrument nurse.