What Structures Form the Costal Margin

The costal margin is the medial margin formed by the cartilages of the seventh to tenth ribs. It attaches to the manubrium and xiphoid process of the sternum. The thoracic diaphragm attaches to the costal margin. The costal angle is the angle between the left and right costal margins where they join the sternum.

What is the costal margin in the body?

Costal margin: The lower edge of the chest (thorax), formed by the bottom edge of the rib cage.

What makes up the costal cartilage?

The costal cartilages are bars of hyaline cartilage that serve to prolong the ribs forward and contribute to the elasticity of the walls of the thorax. Costal cartilage is only found at the anterior ends of the ribs, providing medial extension.