Toraks

Toraks, or thorax, is the central chest region between the neck and abdomen. It is bounded anteriorly by the sternum and costal cartilages, laterally by the ribs and intercostal muscles, posteriorly by the thoracic vertebrae, and inferiorly by the diaphragm. In Turkish medical terminology, toraks denotes this region.

Within the thoracic cavity lie the lungs and heart, enclosed by the pleural sacs and the mediastinum. The mediastinum contains the heart and pericardium, thymus (in children), major vessels, trachea, esophagus, and several nerves. The thorax is protected by the rib cage, spine, and sternum, and its floor is formed by the diaphragm, which plays a key role in breathing.

The thoracic wall comprises skin, muscles including the intercostals and diaphragm. The lungs fill much of the pleural cavities; the left lung has two lobes, the right three, separated by fissures. The pleurae include a visceral layer covering each lung and a parietal layer lining the chest wall; the potential pleural space may accumulate air or fluid in disease (pneumothorax or pleural effusion).

Physiologically, the toraks houses organs essential for respiration and circulation. Breathing expands the chest during inspiration; the diaphragm descends, while intercostal muscles elevate the ribs, decreasing intrathoracic pressure to draw air in.

Developmentally, the thoracic region forms from embryonic somites; growth of lungs occurs within the pleural sacs, and the diaphragm arises from septum transversum. Clinically, thoracic injuries and diseases—trauma, pneumothorax, infections, tumors—affect the thoracic cavity and require imaging, such as X-ray or CT.