Costal margin

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Costal margin

The costal margin is the lower edge of the chest (thorax) formed by the bottom edge of the rib cage. It is an important anatomical landmark in the human body and plays a crucial role in the protection of vital organs within the thoracic cavity.

Anatomy

The costal margin is composed of the cartilages of the seventh to tenth ribs, which are also known as the false ribs. These cartilages connect to the sternum indirectly through the costal cartilages of the ribs above them. The costal margin forms an arch that extends from the xiphoid process of the sternum to the lower border of the tenth rib.

Function

The primary function of the costal margin is to provide structural support and protection to the organs located within the thoracic cavity, including the heart, lungs, and major blood vessels. It also serves as an attachment point for various muscles involved in respiration, such as the diaphragm and the intercostal muscles.

Clinical Significance

The costal margin is a significant landmark in clinical examinations and surgical procedures. It is often used as a reference point for the assessment of the liver and spleen during physical examinations. The costal margin can also be involved in certain medical conditions, such as costochondritis, which is the inflammation of the cartilage connecting the ribs to the sternum.

Related Structures

• Rib cage
• Sternum
• Xiphoid process
• Diaphragm
• Intercostal muscles

See Also

• Thoracic cavity
• Respiratory system
• Musculoskeletal system