sterna

例句：

1. 1. He sat on the edge of the bed, feeling his sterna strain under his weight.
   他坐在床边的边缘，感觉到他的肋骨在重量下感到紧张。
2. 2.The doctor examined her sternum and found no fractures.
   医生检查了她的胸骨，没有发现骨折。
3. 3. She lifted her arms above her head and stretched her sterna.
   她举起她的手臂超过头顶并伸展她的肋骨。