Question

The number of floating ribs in human are
A. 6 pairs
B. 5 pairs
C. 3 pairs
D. 2 pairs

Answer 1

Hint: The rib cage is a structure where the ribs are arranged and attached to the vertebral column and sternum in the thorax. This structure is present in the most vertebrates, that encloses and protects the heart and lungs. In humans, the rib cage, also known as the thoracic cage.

Complete step by step answer: The rib cage, found in a vertebrate animal, a basketlike skeletal structure that forms the chest, or thorax. This structure is made up of the ribs and their corresponding attachments to the sternum which is the breastbone and the vertebral column. The rib cage enclosed the lungs and the heart. This rib cage provides bony protection to the vital organs of the human body.

The rib cage forms the thoracic cage and it consists of the $12$ pairs of ribs, in addition to the sternum and the costal cartilages. The ribs remain anchored to the thoracic vertebrae. The curvature of the rib cage becomes more open with each succeeding rib. The rib cage is semi rigid but it can be stretched i.e. capable to increase in size. The joints present between the ribs and the vertebrae allows a of the ribs motion in the vertebrae which is essential during breathing and other activities.

Generally, in humans, twelve ribs are present on each side of the body i.e. there are a total of twenty-four ribs. Among these twenty-four ribs, the first seven pairs of ribs are called true ribs. The ribs are anchored to the edge of the sternum, or breastbone by the costal cartilages. It is found in the middle of the chest at the front of the body. These ribs are connected to the thoracic vertebra of the spinal column in the back.

The next three pairs of ribs that are eight, nine, and ten are known as false ribs as these do not connect to the sternum individually. The costal cartilage anchors the false ribs to the ribs above them. They jointly build a cartilage connection to the sternum by blending into the cartilage of the rib seventh pair. These ribs are also attached to the thoracic vertebrae in the back.

And the last two pairs of ribs which are the eleventh and twelfth ribs are known as floating ribs. These pairs of ribs only connect to the thoracic vertebrae of the spinal column in the back.
Therefore, the correct option is option D.

Note: The rib cage is the most important part of the human skeleton. It lies at the chest on the front side of the body. This rib cage consists of a number of ribs. The total number of ribs is twenty-four i.e. twelve pairs. Among them, the first seven pairs are called true ribs, the next three pairs of ribs are called false ribs, and the last two pairs of ribs are called floating ribs.