Final answer:
Men typically have 12 pairs of ribs, including true ribs (1-7), false ribs (8-10), and floating ribs (11 and 12), which all form part of the thoracic cage that protects vital organs and supports breathing.
Step-by-step explanation:
Normal Rib Pairs in Men
Normally, men have 12 pairs of ribs. The thoracic cage, commonly known as the rib cage, consists of the sternum, 12 thoracic vertebrae, and these rib pairs. The ribs are categorized into true ribs, false ribs, and floating ribs. The first seven pairs are true ribs, directly attaching to the sternum via cartilage. The next three pairs are false ribs, which connect to the cartilage of the ribs above rather than directly to the sternum. Lastly, the final two pairs are known as floating ribs because they are not attached to the sternum at all but to muscles in the abdominal wall.
The thoracic cage is important in its function to protect vital organs such as the heart and lungs. Each rib is a curved, flattened bone that articulates with the thoracic vertebrae and has a costal groove for the passage of blood vessels and a nerve. The anatomy of the ribs and the sternum work together to form the structure that supports breathing and shields the upper part of the trunk.