How many sacral vertebrae are listed?

How many sacral vertebrae are listed?

• A. 4
• B. 5
• C. 3
• D. 6

Answer: (A)

The sacrum is formed from five sacral vertebrae that fuse into a single bone. In standard anatomy, you count five sacral vertebral segments (S1–S5), even though they are fused in the adult. So the usual answer is five, because you’re counting the original vertebral segments that make up the sacrum. If a diagram or source shows four, it might be a simplification or variation, but the typical, correct count in anatomy is five.

The sacrum is formed from five sacral vertebrae that fuse into a single bone. In standard anatomy, you count five sacral vertebral segments (S1–S5), even though they are fused in the adult. So the usual answer is five, because you’re counting the original vertebral segments that make up the sacrum. If a diagram or source shows four, it might be a simplification or variation, but the typical, correct count in anatomy is five.