Question

The number of 'true ribs' in a man is:
A) 12 pair
B) 7 pair
C) 3 pair
D) 2 pair

Answer 1

Hint:
The vertebral column protects the spinal cord, supports the head, and serves as a point of attachment for the ribs and musculature of the back. The flat bone on the ventral midline of thorax is sternum. In the human body, there are 12 ribs.

Complete step by step answer:
Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum. It has two articulation surfaces on its dorsal end so it is known as bicephalic. True ribs are the first seven ribs. These are attached dorsally to the thoracic vertebrae and these are connected ventrally to the sternum with the help of hyaline cartilage. The pair of ribs that do not articulate directly with the sternum are the 8^th, 9^th, and 10^th pairs. But these join directly with the seventh rib with the help of hyaline cartilage. These are known as false ribs or vertebrochondral ribs. The 11^th and 12^th pairs of ribs are not connected ventrally so these are named floating ribs. The rib cage consists of thoracic vertebrae, ribs, and sternum.

Option ‘B’ is correct

Note:
The axial skeleton comprises 80 bones distributed along the main axis of the body. The axial skeleton consists of ribs, sternum, skull, and vertebral column. The skull has a total of 22 bones i.e., cranial and facial. Cranial bones form the hard protective outer covering cranium of the brain.