Chest wall

Chest wall

Latin	Paries thoracis

The chest wall (also known as the thoracic wall) is the boundary that protects and encloses the thorax, or chest. It provides the mechanical basis for breathing and is crucial in the protection of the vital organs within the thoracic cavity, including the heart, lungs, and esophagus. The chest wall is comprised of the sternum, rib cage, and thoracic vertebrae. It also includes the skin, muscles, and connective tissues that enclose the thoracic cavity.

Structure

The chest wall is structured to maintain the necessary rigidity and flexibility for respiration. It consists of several components:

Bones

• Sternum: A flat bone at the front of the chest to which the ribs connect via costal cartilage.
• Ribs: Twelve pairs of long curved bones which form the protective cage around the thoracic organs.
• Thoracic vertebrae: The part of the vertebral column that corresponds to the chest, providing posterior support.

Muscles

• Intercostal muscles: Located between the ribs, these muscles help expand and contract the thoracic cavity during breathing.
• Pectoralis major: A large muscle on the upper chest that aids in the movement of the shoulder.
• Pectoralis minor: A smaller muscle beneath the pectoralis major, which also assists in shoulder movements.

Other components

• Skin and subcutaneous tissue: Cover the external surface of the chest wall.
• Fascia: Connective tissue layers that encase and define the chest wall muscles.

Function

The primary function of the chest wall is to protect the organs within the thorax and resist the negative internal pressures generated during inspiration. The rigidity of the ribs and sternum allows for protection against physical trauma, while the flexibility of the muscles and joints allows for the expansion and contraction necessary for respiration.

Clinical significance

The chest wall can be affected by various medical conditions:

• Fractures: Commonly involve the ribs and sternum due to trauma.
• Infections: Such as osteomyelitis of the rib or sternal area.
• Cancers: Primary tumors of the chest wall are rare, but metastasis from other sites can occur.
• Deformities: Such as pectus excavatum (sunken chest) and pectus carinatum (pigeon chest).

See also

• Thorax
• Human skeleton
• Respiratory system