- Also called:
- chest cavity
- Related Topics:
- Thorax
- body cavity
thoracic cavity
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What is the thoracic cavity?
The thoracic cavity, the body's second largest hollow space, is enclosed by the ribs, vertebral column, and sternum, and separated from the abdominal cavity by the diaphragm.
It contains the lungs, tracheobronchial tree, heart, blood vessels between the heart and lungs, great arteries, major veins, and esophagus. The heart is covered by the pericardium.
The chest cavity is lined by the parietal pleura, with the visceral pleura covering the lung and the mediastinal pleura covering the esophagus, heart, and great vessels. The mediastinum is the space between the lungs.
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Where is the thoracic cavity located in the human body?
The thoracic cavity, or chest, is located in the vertebrate body between the neck and the abdomen. It is a basket-like structure formed by the rib cage, which consists of the ribs and their attachments to the sternum (breastbone) and vertebral column.
Within the thoracic cavity are the chief organs for respiration and circulation, including the lungs, air passages, heart, and major blood vessels. The diaphragm bounds it from below. The mediastinum, a division of the thoracic cavity, is the anatomic region between the lungs that contains the heart, thymus gland, and portions of the esophagus and trachea. The pleura lines the thoracic cavity and covers the lungs.
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Which major organs are found in the thoracic cavity?
The thoracic cavity, the body's second-largest hollow space, is enclosed by the ribs, vertebral column, and sternum, and separated from the abdominal cavity by the diaphragm.
Major organs in the thoracic cavity:
* The heart
* The lungs
* The trachea and lower airways
* The esophagus
* Major blood vessels, including the aorta and vena cava
* The thymus glandThe mediastinum, a division within the thoracic cavity, houses the heart, thymus gland, and portions of the esophagus and trachea. The thoracic cavity is lined by the parietal pleura, with the visceral pleura covering the lungs, and the mediastinal pleura covering the esophagus, heart, and major vessels.
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What are the main functions of the thoracic cavity?
The thoracic cavity, protected by the rib cage, houses critical organs and facilitates respiration. The diaphragm, a primary respiratory muscle, separates the thoracic and abdominal cavities; its contraction expands the thoracic cavity, enabling air intake, while relaxation aids exhalation.
The lungs within the thorax, are responsible for gas exchange, supplying oxygen and removing carbon dioxide. The mediastinum, located between the lungs, contains the heart, trachea, esophagus, and thymus gland.
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How is the thoracic cavity separated from the abdominal cavity?
The thoracic and abdominal cavities in mammals are separated by the diaphragm, a dome-shaped, muscular and membranous structure, and the principal muscle of respiration. The muscles of the diaphragm arise from the lower part of the sternum, the lower six ribs, and the lumbar vertebrae of the spine. These muscles are attached to a central membranous tendon. The diaphragm is essential in actions such as coughing, sneezing, vomiting, crying, and expelling feces and urine.
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What roles do the ribs and diaphragm play in the thoracic cavity?
Within the thoracic cavity, the ribs and diaphragm are key to respiration. The rib cage, composed of 12 thoracic vertebrae, 24 ribs, and the sternum, protects internal organs and expands to facilitate breathing. Ribs are connected to the sternum via costal cartilages; the first seven are true ribs, while the remaining five are false ribs. The diaphragm, a dome-shaped muscle, separates the thoracic and abdominal cavities and is essential for respiration. Its contraction increases the thoracic cavity's volume, decreasing pressure and allowing air to enter the lungs (inspiration). Relaxation of the diaphragm, along with the elastic recoil of lung tissue and the thoracic cage, causes expiration.
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thoracic cavity, the second largest hollow space of the body. It is enclosed by the ribs, the vertebral column, and the sternum, or breastbone, and is separated from the abdominal cavity (the body’s largest hollow space) by a muscular and membranous partition, the diaphragm. It contains the lungs, the middle and lower airways—the tracheobronchial tree—the heart, the vessels transporting blood between the heart and the lungs, the great arteries bringing blood from the heart out into general circulation, and the major veins into which the blood is collected for transport back to the heart. The heart is covered by a fibrous membrane sac called the pericardium that blends with the trunks of the vessels running to and from the heart. The thoracic cavity also contains the esophagus, the channel through which food is passed from the throat to the stomach.
The chest cavity is lined with a serous membrane, which exudes a thin fluid. That portion of the chest membrane is called the parietal pleura. The membrane continues over the lung, where it is called the visceral pleura, and over part of the esophagus, the heart, and the great vessels, as the mediastinal pleura, the mediastinum being the space and the tissues and structures between the two lungs. Because the atmospheric pressure between the parietal pleura and the visceral pleura is less than that of the outer atmosphere, the two surfaces tend to touch, friction between the two during the respiratory movements of the lung being eliminated by the lubricating actions of the serous fluid. The pleural cavity is the space, when it occurs, between the parietal and the visceral pleura.
The pleura is a continuous sheet of endothelial, or lining, cells supported by a thin base of loose connective tissue. The membrane is well supplied with blood vessels, nerves, and lymph channels. The vessels of the visceral part of the pleura are intimately related with those of the lungs and bronchi; its arteries are branches of the bronchial arteries, and its veins mingle with the pulmonary network of capillaries. Beneath its inner side is a network of tiny lymph channels, or capillaries, that penetrate the lung substance, or parenchyma, and drain to the lymph nodes at the hilus of each lung, the point of entrance and departure for bronchi, blood vessels, and nerves.
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Diseases affecting the pleura and pleural cavity, other than primary tumours, are brought by the blood vessels or may spread from contiguous structures. The pleural cavity may be contaminated by the rupture of either the visceral pleura or the parietal pleura.
Accumulation of fluid in the pleural cavity is called hydrothorax. If the fluid is bloody, the condition is described as hemothorax; if it contains pus, pyothorax. The accumulation of fluid may or may not be accompanied by air. When air is present, the affix -pneumo- is inserted into each of the names mentioned—e.g., hydropneumothorax.
The penetration of air into the pleural cavity from outside, as from a penetrating wound of the chest, or from within, by rupture of dilated alveoli (air sacs of the lung) or of a cyst, will produce a pneumothorax, converting this cavity into a positive pressure chamber and collapsing the lung, which in turn will lead to decreased oxygenation of the venous blood. The collapse may also have a deleterious effect on the heart.
Inflammation of the pleura, usually diffuse, affecting one or both sides, is called pleurisy. Two forms are distinguished: (1) simple, dry, or fibrinous pleurisy; and (2) exudative pleurisy, in which the membrane gives off excessive fluid. Since the pleura is well supplied by nerves, pleurisy can be extremely painful, especially as the lung moves in respiration. Common symptoms are pain, shortness of breath, and fever. Treatment is directed toward evacuation of fluid and alleviation of the underlying condition, often an infected lung but more rarely a diffuse inflammatory condition such as rheumatoid arthritis.
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Rupture of the thoracic duct, the main channel for lymph, gives rise to chylothorax, characterized by escape of lymph into the pleural space.
Epidemic pleurodynia, or Bornholm disease, is an acute infection of the various tissues of the pleural cavity by group B coxsackieviruses or certain other enteroviruses. The disease is characterized by a general feeling of ill health and by pain in the chest muscles and the upper part of the abdomen. That pain is usually increased by respiration and cough, and pain in other muscles is often present. The condition subsides in two to five days but sometimes may take weeks to disappear.