Which of the following form thoracic cage of man?

Options

A. Ribs and sternum
B. Ribs and thoracic vertebrae
C. Ribs, sternum and lumber vertebrae
D. Ribs, sternum and throraic vertebrae

Answer

To determine which of the following forms the thoracic cage of man, we need to understand the components that make up the thoracic cage, also known as the ribcage.

### Step-by-Step Solution:

1. **Definition of Thoracic Cage**: The thoracic cage, or ribcage, is a bony structure that surrounds the thoracic cavity. It plays a crucial role in protecting vital organs such as the heart and lungs.

2. **Components of the Thoracic Cage**: The thoracic cage is primarily made up of:
- **Ribs**: There are 12 pairs of ribs that curve around the thoracic cavity.
- **Sternum**: This is the flat bone located at the front of the ribcage.
- **Thoracic Vertebrae**: These are the 12 vertebrae located in the middle of the spine that correspond to the ribs.

3. **Analyzing the Options**:
- **Option 1**: Ribs and sternum - This option is incorrect because it does not include the thoracic vertebrae.
- **Option 2**: Ribs and thoracic vertebrae - This option is incorrect because it does not include the sternum.
- **Option 3**: Ribs, sternum, and lumbar vertebrae - This option is incorrect because it includes lumbar vertebrae instead of thoracic vertebrae.
- **Option 4**: Ribs, sternum, and thoracic vertebrae - This option is correct as it includes all the necessary components of the thoracic cage.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 4**: Ribs, sternum, and thoracic vertebrae.