Musculus extensor

例句：

1. 1. The muscles in the back are responsible for extending the spine.
   背部的肌肉负责伸展脊柱。
2. 2. The physiotherapist used a series of exercises to strengthen and extend the patient's muscles.
   物理治疗师使用一系列锻炼来加强并伸展患者的肌肉。
3. 3. The doctor advised him to stretch his muscles regularly to prevent injuries.
   医生建议他定期伸展肌肉以防止受伤。