Most humans have 24 ribs, arranged in 12 pairs. This is consistent across both males and females.
Variations in Rib Count
While 24 is the typical number, variations do exist. A small percentage of the population (approximately 1 in 500) may possess an extra rib, known as a cervical rib. This extra rib can appear on the right, left, or both sides of the body.
Rib Anatomy
Each rib is a thin, flat bone attached to the spinal column at the back and, typically, to the sternum (breastbone) in the front. Ribs are numbered 1 through 12, corresponding to the vertebra to which they attach.
- True ribs (1-7): Directly connect to the sternum via their own cartilage.
- False ribs (8-10): Connect indirectly to the sternum through shared cartilage with the ribs above.
- Floating ribs (11-12): Do not connect to the sternum at all.
Why the Variation?
The presence or absence of a cervical rib is often due to genetic variations.
Sources
- Multiple sources including Healthline, Medical News Today, Byju's, Britannica, and Wikipedia all corroborate the information presented above regarding the typical number of ribs in humans and the possibility of variations. Specific details like the frequency of cervical ribs (1 in 500) are mentioned in some of these references.
