Question

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

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

Answer 1

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

There are 12 pairs of ribs. The first seven pairs of ribs are called true ribs. They are dorsally attached to the thoracic vertebral column and ventrally connected to the sternum with the help of the hyaline cartilage. The 8th, 9th and 10th pairs of ribs join the seventh rib only with the help of hyaline cartilage. Hence they are called false ribs. The last two pairs of ribs are not connected ventrally and are therefore, called floating ribs.