ICSE

The last two, the 11th and 12th pairs of ribs are not attached to the sternum and are known as floating ribs.

There are twelve pairs of ribs which along with the thoracic vertebrae and the sternum constitute the bony cage or rib cage.

The sternum is a long flat bone lying in the middle of the front part of the chest.

The vertebral or spinal column is popularly called the backbone. It is composed of a total of 33 individual ring-like bones called vertebrae.

Skull is the skeleton of the head. It contains two parts. The upper top part of the cranium is made of eight bones that are so joined to each other that they are permanently fixed. The other part of the skull forms the face which contains a total of fourteen bones.

The two main divisions of the skeleton are: Axial skeleton Appendicular

The two types of bone marrow are: Yellow marrow Red marrow

There are four types of bones: Long bones Short bones Flat bones Irregular bones

Bones comprise the hard framework of the body.

There are three constituents of the skeleton:- Bones Cartilages Ligaments