How many pairs of ribs compose the thoracic cage?

The thoracic cage, also known as rib cage, is composed of 12 pairs of ribs. It is comprised of bony and cartilagenous structures. It is surrounded by the thoracic cavity, and it supports the shoulder girdle.

The thoracic cage has three primary components, which are the ribs and costal cartilages, the thoracic vertebrae and their intervertebral discs, and the sternum (also known as the breast bone). It provides attachments for muscles of the upper limbs, neck, thorax, back and abdomen.

The ribs are flattened, twisted and elongated bones. They are lightweight and resilient. The three types of ribs are the floating ribs, true ribs and false ribs.