Rib 5

The rib 5 (fifth rib) is a true rib that articulates posteriorly with the thoracic vertebrae (T5) and anteriorly with the sternum via costal cartilage. The fifth rib is classified as a true rib, meaning it has a direct cartilaginous connection to the sternum.

Anatomically, the fifth rib has several key features:

• Head: The head of the rib articulates with the bodies of the T3 and T4 vertebrae.

• Neck: The neck is a flattened portion that extends laterally from the head.

• Tubercle: The tubercle is a small bump on the posterior surface of the rib, which articulates with the transverse process of the T4 vertebra.

• Body (shaft): The body is the main, curved part of the rib. It has a superior border, which is rounded and smooth, and an inferior border, which is sharp and contains the costal groove for the intercostal vessels and nerve.

• Costal cartilage: The anterior end of the rib connects to the sternum via costal cartilage, which provides flexibility to the thoracic cage.