Question

Number of pairs of floating ribs in human body is-
A. 6 pair
B. 5 pair
C. 3 pair
D. 2 pair

Answer 1

Hint: Human body is formed of bones that comprise the skeletal system. The vertebral column is a part of it and is also known as the spinal column, backbone, or spine. Paired ribs arise from vertebrae of the thoracic region. The human consists of 12 pairs of ribs. They collectively form the rib cage.

Complete answer:
The flexible column made of ribs extending from the neck to tail made up of bones called vertebrae. The humans contain vertebral columns so as to protect the spinal cord. The 12 pairs of ribs are attached to the vertebral column in the thoracic region in order to make the thoracic cavity. It also helps in walking and standing.
The human vertebral column has further divided into-
Cervical vertebrae- It starts from the very first bone that is Atlas and these vertebrae are seven in number. (1-7).
Thoracic vertebrae- It starts from after the 7th one and is 12 in number(8-19).
Lumbar vertebrae- They comprise of the lumbar portion and are 5 in number.

In this vertebral column, the ribs are the long bones that form the whole of the rib cage and are 12 pairs which are classified as –
> True ribs- 1-7
> False ribs- 8-10
> Floating ribs- 11-12
All these ribs are ventrally connected to Sternum but the 11th and 12th pairs are called floating ribs because they are not attached to the sternum.

The number of pairs of floating ribs in the human body is 2 pairs. So, the correct answer is option (D).

Additional information: The floating ribs are known to have Slipping rib syndrome as they are not attached and are more prone to injury.

Note:
The vertebral column is different in different organisms, the basic difference arises in the position of bones and also remember that it is only present in chordates. All the members of Non chordata are devoid of notochord or vertebral columns.
The ribs arise from the thoracic vertebrae and form a cage to protect lungs and heart. The intercostal muscles of the ribs also help during breathing.