Question

What are the different types of rib bones that form the rib cage?

Answer 1

Rib cage is a part of the axial skeleton, therefore this is formed by all the bones which are part of the axial skeleton but not the skull. None of the bones of the appendicular skeleton is part of the rib cage.

Complete answer: The rib cage is also called a thoracic cage as it is present in the thoracic cavity above the abdomen. It is formed by ribs, sternum, and thoracic vertebrae. It is an airtight chamber.
There are 12 pairs of ribs that total 24 ribs, 12 thoracic vertebrae, and a single flat sternum. Therefore, this thoracic cage is formed of 37 bones. These bones are attached to each other by cartilages.
The rib cage is formed ventrally by the sternum, dorsally by the thoracic vertebrae, laterally by the ribs, and on the lower side by a muscular separator called the diaphragm. The diaphragm separates the thoracic cavity and the abdominal cavity.
In the rib cage, out of the 12 pairs, the first 7 pairs of the ribs are called true ribs because they are directly attached to the sternum with the help of hyaline cartilage. The $8^{th}$, $9^{th}$, and $10^{th}$ pair are not directly attached to the sternum.
The $8^{th}$, $9^{th}$, and $10^{th}$ pair of ribs are connected to the $7^{th}$ rib with the help of hyaline cartilage and hence they are called false ribs. The last two pairs of ribs are connected only to the vertebral column and hence they are called floating ribs.
Sternum which is also called breast bone is a long and flat bone present on the ventral side of the thoracic chamber. It is about 15 cm to 17 cm in length. It has three regions namely – Manubrium, Body, and Xiphoid process.
Each rib is a thin flat bone that has a ventral connection to the sternum with the help of hyaline cartilage and dorsal connection to the vertebral column. Each rib is bicephalic since it has two articulation surfaces on its dorsal end.
Rib cage or thoracic cage gives proper shape to the thorax and protects the lungs and the heart present in it. During breathing or pulmonary ventilation, the rib cage plays an important role along with intercostal muscles and the muscular diaphragm.

Note: True ribs are called vertebrosternal ribs since they are connected to both the vertebral column and sternum. False ribs are called vertebrochondral ribs , since they are connected to the vertebral column, and cartilage and floating ribs are called vertebral ribs since they are connected only to vertebral columns.