11th and 12 the pairs of ribs are called

Options

A. true ribs
B. false ribs
C. vertebrochondral ribs
D. floating ribs

Answer

To solve the question regarding the 11th and 12th pairs of ribs, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Ribs**:
- Ribs are categorized into different types based on their attachment to the sternum. The main types are:
- True ribs
- False ribs
- Vertebrochondral ribs
- Floating ribs

2. **Define True Ribs**:
- True ribs are the first 7 pairs (1st to 7th pairs) of ribs. They are called true ribs because they are directly attached to the sternum.

3. **Define False Ribs**:
- False ribs consist of the 8th and 9th pairs. They are termed false ribs because they are indirectly attached to the sternum.

4. **Define Vertebrochondral Ribs**:
- The 10th pair of ribs is known as vertebrochondral ribs. They are also indirectly attached to the sternum.

5. **Define Floating Ribs**:
- The 11th and 12th pairs of ribs are called floating ribs. They are termed floating ribs because they do not attach to the sternum at all, neither directly nor indirectly.

6. **Conclusion**:
- Therefore, the correct answer to the question is that the 11th and 12th pairs of ribs are called **floating ribs**.

### Final Answer:
The 11th and 12th pairs of ribs are called **floating ribs**.

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