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 = 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. Each rib is a thin flat bone.

The first seven pairs of ribs are attached dorsally to the thoracic vertebrae and ventrally to the sternum with the help of hyaline cartilage. They are called true ribs.

The 8th, 9th and 10th pairs of ribs do not join directly to the sternum but join the seventh rib with the help of hyaline cartilage. These are called false ribs.

The last 2 pairs of ribs are not connected ventrally and are therefore, called floating ribs.