Ribs are curved bones that form the rib cage, protecting the heart and lungs while assisting in breathing.
Rib Count and Structure:
Total ribs: 24 ribs (12 pairs)
Arrangement: Ribs are attached to the thoracic vertebrae at the back
Classification of Ribs: Types of Ribs:
True Ribs (Vertebrosternal ribs): Pairs 1-7
Attached directly to the sternum (breastbone) via costal cartilage
False Ribs (Vertebrochondral ribs): Pairs 8-10
Not directly attached to sternum
Their cartilage joins with the cartilage of the 7th rib
Floating Ribs (Vertebral ribs): Pairs 11-12
No anterior attachment to sternum
Only attached to vertebrae at the back
Why 24 is Correct:
12 pairs × 2 = 24 ribs total
This is the standard number in human anatomy
Rare anatomical variations exist (cervical rib or missing rib), but 24 is normal
Why Other Options are Incorrect:
(A) 20: Too few; would mean only 10 pairs
(B) 22: 11 pairs; incorrect count
(D) 28: Too many; would mean 14 pairs
Functions of Ribs:
Protect vital organs (heart, lungs, major blood vessels)
Provide attachment points for respiratory muscles
Assist in breathing by expanding and contracting
Final Answer: 24
