Question

figure 7.5 is a lateral view of the vertebral column. identify each numbered region of the column by listing in the answer blanks the region name first and then the specific vertebrae involved (for example, sacral region, $s_1$ to $s_5$). also identify the modified vertebrae indicated by numbers 6 and 7 in figure 7.5. select different colors for each vertebral region, and use them to color the coding circles and the corresponding regions.
1.
2.
3.
4.
5.
6.
7.
which vertebra allows you
to nod \yes\?
... shake
o\?

Explanation:

To nod "yes", the atlas (C₁) and axis (C₂) are involved, but the primary vertebra for nodding is the atlas (C₁) and the axis (C₂) allows rotation, but the nodding motion (flexion/extension) is mainly at the atlanto - occipital joint (involving the occipital bone and C₁). However, the vertebra that allows nodding "yes" is the atlas (C₁) and the axis (C₂) for shaking "no" (rotation). But the most common answer for nodding "yes" is the atlas (C₁) and for shaking "no" is the axis (C₂). But looking at the diagram, 6 and 7 are likely the atlas and axis. Wait, the question is "Which vertebra allows you to nod 'yes'?". The atlas (C₁) and the occipital bone form the joint for nodding (flexion - extension), but the vertebra here is C₁ (atlas). For shaking "no", it's C₂ (axis) as it allows rotation. But in the diagram, 6 and 7 are probably C₁ (atlas) and C₂ (axis). So for nodding "yes", the vertebra is the atlas (C₁, which is likely number 6 or 7? Wait, the diagram has 6 and 7 at the top. So 6 is likely the atlas (C₁) and 7 is the axis (C₂). So nodding "yes" is allowed by the atlas (C₁, number 6? Or 7? Wait, the atlas is C₁, axis is C₂. The atlanto - occipital joint (between occipital and C₁) allows nodding (flexion/extension), so the vertebra here is C₁ (atlas, number 6 maybe). For shaking "no", it's C₂ (axis, number 7) as it allows rotation of the head.

Answer:

To nod "yes": Atlas (C₁, likely the vertebra labeled 6 in the diagram)
To shake "no": Axis (C₂, likely the vertebra labeled 7 in the diagram)

For the vertebral column regions:

1. Cervical region, \( C_1 \) to \( C_7 \)
2. Thoracic region, \( T_1 \) to \( T_{12} \)
3. Lumbar region, \( L_1 \) to \( L_5 \)
4. Sacral region, \( S_1 \) to \( S_5 \) (fused)
5. Coccygeal region, \( Co_1 \) to \( Co_4 \) (fused)
6. Atlas (\( C_1 \)) (modified vertebra)
7. Axis (\( C_2 \)) (modified vertebra)