sternomastoideus muscle

例句：

1. 1. The sternomastoideus muscle is responsible for lifting the sternum up and out of the chest.
   胸骨上提肌负责将胸骨抬起并移出胸腔。
2. 2. During surgery, the surgeon needs to retract the sternomastoideus muscle to access the heart.
   在手术中，外科医生需要拉回胸骨上提肌以便接触心脏。
3. 3. The patient's condition required the sternomastoideus muscle to be released to facilitate breathing.
   患者的病情需要胸骨上提肌被释放以便于呼吸。