Which of the following correlations are incorrect?

Options

A. There are seven free cervical vertebrae and seven pairs of cervical spinal nerves
B. There are twelve free thoracic vertebrae and twelve pairs of thoracic spinal nerves
C. There are five free lumber vertebrae and five pairs of lumbar spinal nerves
D. There are five fused sacral vertebrae and five pairs of sacral spinal nerves

Answer

To determine which correlations are incorrect, let's analyze each statement step by step:

1. **Cervical Vertebrae and Spinal Nerves**:
- There are **7 cervical vertebrae** (C1 to C7).
- However, there are **8 pairs of cervical spinal nerves** (C1 to C8).
- **Conclusion**: This statement is **incorrect** because it states there are only 7 pairs of cervical spinal nerves, while there are actually 8.

2. **Thoracic Vertebrae and Spinal Nerves**:
- There are **12 thoracic vertebrae** (T1 to T12).
- There are also **12 pairs of thoracic spinal nerves**.
- **Conclusion**: This statement is **correct**.

3. **Lumbar Vertebrae and Spinal Nerves**:
- There are **5 lumbar vertebrae** (L1 to L5).
- There are also **5 pairs of lumbar spinal nerves**.
- **Conclusion**: This statement is **correct**.

4. **Sacral Vertebrae and Spinal Nerves**:
- There are **5 sacral vertebrae**, which are fused (S1 to S5).
- There are also **5 pairs of sacral spinal nerves**.
- **Conclusion**: This statement is **correct**.

### Final Summary:
- The only incorrect correlation is the first one regarding cervical vertebrae and spinal nerves.