Question

Out of 'X' pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation.

• A. $X=24,Y=12$ True ribs are dorsally attached to vertebral column but are free on ventral side
• B. $X=12,Y=7$ True ribs are attached dorsally to vertebral column and ventrally to the sternum
• C. $X=12,Y=5$ True ribs are attached dorsally to vertebral column and sternum on the two ends
• D. $X=24,Y=7$ True ribs are dorsally attached to vertebral column but are free on ventral dise

Answer 1

The correct option is B $X=12,Y=7$ True ribs are attached dorsally to vertebral column and ventrally to the sternum

In the rib cage, there are 12 pairs of bones. Out of 12, the first 7 pairs are the true ribs as they are directly attached to the sternum and vertebral column. Whereas the last 5 pairs only attach to the vertebral column and indirectly attach to the sternum. Out of 5 pairs, 7 - 10 attached to the costal cartilage and called false ribs, and the last 11th and 12th have no interior attachment and called floating ribs. Thus, the correct answer is option B.