摘要：Background Traditional techniques used for harvesting the pectoralis major myocutaneous （PMMC） flap have accompanying disadvantages,such as the necessity for an upper chest skin incision,the bulkiness of myocutaneous tissue at the pedicle of the flap,and the risk of total or partial necrosis of flap *** aim of this study was to develop a safe and fast method for preparing PMMC island flaps using preoperative ultrasonography for vessel *** Forty-one PMMC island flaps were used for one-stage reconstruction of head and neck defects,including 21 cases in the treatment group and 20 cases in the control *** the treatment group,ultrasonography was used to mark out the course of the thoracic branches of the thoracoacromial artery and the lower end of this artery perforating from the fascia into the muscles,as well as the largest perforating branch of the fourth or fifth internal mammary artery entering the PMMC flap.A line,from the lower end of the thoracic branch to the largest perforating branch of the fourth or fifth internal mammary artery,was drawn to determine the axis of the PMMC *** the control group,PMMC island flaps were designed according to conventional methods without using *** According to the ultrasonic marks,the distance from lower end of thoracic branch to the midpoint of the margin of the inferior clavicular was （5.1±1.2） *** time from designing to transferring the island flap was significantly shorter in the treatment group （（51.0±10.5） minutes） compared with the control group （（78.0±13.9） minutes,P 〈0.01）.The rate of partial necrosis was 4.7% （1/21） in the treatment group and 35.0% （7/20） in the control *** was one case of flap failure in the control group due to vascular injury during vascular pedicle *** Preoperative vessel detection by ultrasonography facilitates easy and safe harvesting of the true PMMC island flap.