How many true ribs do humans have:
A. three
B. fifteen
C. five
D. twelve
E. seven
The Correct Answer and Explanation is:
The correct answer is E. seven.
Humans have 12 pairs of ribs, which are divided into three categories: true ribs, false ribs, and floating ribs.
- True ribs (also called vertebrosternal ribs) are the first seven pairs of ribs. These ribs are directly attached to the sternum (breastbone) by their own costal cartilage. This direct attachment is what distinguishes true ribs from false ribs.
- False ribs (pairs 8 to 10) are indirectly attached to the sternum. Instead of having their own cartilage that connects directly to the sternum, they connect to the cartilage of the rib above them.
- Floating ribs (pairs 11 and 12) do not have any attachment to the sternum. They are also known as vertebral ribs because they are only attached to the vertebrae at the back.
The true ribs are considered the first seven pairs because they have a direct attachment to the sternum through their own individual cartilage, making them “true” in their connection. This direct connection allows for more flexibility and mobility in the chest area, which is essential for breathing.
The purpose of the ribs, including the true ribs, is to protect vital organs such as the lungs, heart, and liver. They also assist in the process of breathing by expanding and contracting the chest cavity, enabling the lungs to inhale and exhale air.
Thus, the human body has seven true ribs out of the 12 total pairs. This anatomical structure is important for maintaining the integrity of the chest and supporting respiration.