From the Guidelines
The thorax is bordered superiorly by the thoracic inlet, inferiorly by the diaphragm, anteriorly by the sternum and costal cartilages, posteriorly by the thoracic vertebrae and portions of the ribs, and laterally by the ribs and intercostal spaces. These borders create a protective cage-like structure that houses vital organs including the heart, lungs, major blood vessels, and portions of the esophagus and trachea. The thoracic cavity is not a rigid container but rather a dynamic space that changes volume during respiration as the diaphragm contracts and relaxes, and the ribs move. Understanding these anatomical boundaries is essential for clinical examinations, surgical approaches, and diagnostic imaging interpretation of the chest region, as highlighted in recent studies such as 1.
Some key points to consider when evaluating the thorax include:
- The thoracic inlet is formed by the first thoracic vertebra posteriorly, the first ribs laterally, and the superior border of the sternum anteriorly.
- The diaphragm separates the thoracic cavity from the abdominal cavity and plays a crucial role in respiration.
- The sternum and costal cartilages form the anterior border of the thorax, while the thoracic vertebrae and portions of the ribs form the posterior border.
- The ribs and intercostal spaces form the lateral borders of the thorax, as noted in studies such as 1.
- The thoracic cavity contains vital organs, including the heart, lungs, major blood vessels, and portions of the esophagus and trachea, and its dynamic nature is important for respiratory function, as discussed in 1.
Overall, a thorough understanding of the thorax and its borders is critical for accurate diagnosis and treatment of various thoracic conditions, and should be based on the most recent and highest quality evidence, such as 1.
From the Research
Thorax Borders
The borders of the thorax are not explicitly defined in the provided studies, but we can infer some information from the descriptions of the thoracic outlet and inlet.
- The thoracic outlet is bounded by the clavicle, first thoracic rib, insertion of the pectoralis minor muscle onto the coracoid process of the humerus, and the sternum 2.
- The thoracic inlet is the junction between the neck and the chest, and it is not explicitly defined as a border of the thorax, but rather as a region where the neck and chest meet 3.
Related Anatomy
The thorax is related to several other anatomical structures, including:
- The axilla, through which the subclavian vein, subclavian artery, and brachial plexus travel from their central origins to their peripheral termini 2.
- The cervical spine and mediastinum, which are connected to the thoracic outlet 4.
- The pectoralis minor muscle, which plays a role in defining the boundaries of the thoracic outlet 2, 4.