In man, the rib cage is formed by

Options

A. Ribs and thoracic
B. Ribs and sternum
C. Ribs, sternum and vertrbrae
D. Ribs, sternum and thoracic vertebrae.

Answer

### Step-by-Step Solution:

1. **Understanding the Components of the Rib Cage**:
The rib cage is a bony structure that protects vital organs in the thoracic cavity, including the heart and lungs. It is primarily composed of three main components: ribs, sternum, and thoracic vertebrae.

2. **Identifying the Ribs**:
The rib cage consists of 12 pairs of ribs. These ribs are curved bones that extend from the vertebral column at the back and attach to the sternum at the front. The ribs can be categorized into three types: true ribs (first seven pairs), false ribs (next three pairs), and floating ribs (last two pairs).

3. **Understanding the Sternum**:
The sternum, also known as the breastbone, is a flat bone located in the center of the chest. It serves as the anterior attachment point for the ribs. The ribs connect to the sternum via costal cartilage, allowing for flexibility during breathing.

4. **Identifying the Thoracic Vertebrae**:
The thoracic vertebrae are the 12 vertebrae located in the middle segment of the vertebral column. Each rib is attached to a thoracic vertebra at the back, providing structural support and stability to the rib cage.

5. **Conclusion**:
Therefore, the rib cage in humans is formed by the ribs, sternum, and thoracic vertebrae. This structure not only protects the vital organs but also plays a crucial role in the respiratory system by facilitating breathing.

### Final Answer:
The rib cage in man is formed by the ribs, sternum, and thoracic vertebrae.

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