The abdominopelvic cavity is lined with a serous membrane called the peritoneum. This membrane expands from the internal surface of the abdominal wall to completely or partially surround organs of the abdominopelvic cavities.

The mediastinum is a division of the thoracic cavity; it contains the heart, thymus gland, portions of the esophagus and trachea, and other structures.

The abdominopelvic cavity is a body cavity that consists of the abdominal cavity and the pelvic cavity. It contains the stomach, liver, pancreas, spleen, gallbladder, kidneys, and most of the small and large intestines.

Thoracic cavity: The chest; contains the trachea, bronchi, lungs, esophagus, heart and great blood vessels, thymus gland, lymph nodes, and nerve,. as well as the following smaller cavities: Pleural cavities: Surround each lung.

The abdominal cavity contains the greater part of the digestive tract, the liver and pancreas, the spleen, the kidneys, and the adrenal glands located above the kidneys.

[2] The thoracic cavity contains organs and tissues that function in the respiratory (lungs, bronchi, trachea, pleura), cardiovascular (heart, pericardium, great vessels, lymphatics), nervous (vagus nerve, sympathetic chain, phrenic nerve, recurrent laryngeal nerve), immune (thymus) and digestive (esophagus) systems.

The lungs lie either side of the mediastinum, within the thoracic cavity. Each lung is surrounded by a pleural cavity, which is formed by the visceral and parietal pleura.

The thoracic cavity has three compartments: the mediastinum and two pleural cavities. The mediastinum is home to the heart, trachea, great vessels, and some other structures. The pleural cavities are on either side of the mediastinum and contain the lungs and the pleural linings.

Also on defense inside the chest is the liver, the body’s largest glandular organ. Both the liver and the stomach are located in the lower chest region under the thoracic diaphragm, a sheet of muscle at the bottom of the rib cage that separates the chest cavity from the abdominal cavity.

Your lower esophagus, stomach, intestines, liver, and kidneys are below the diaphragm, in your abdominal cavity.

The diaphragm

There are two layers; the outer pleura (parietal pleura) is attached to the chest wall and the inner pleura (visceral pleura) covers the lungs and adjoining structures, via blood vessels, bronchi and nerves.

Pneumothorax occurs when air enters the space around your lungs (the pleural space). Air can find its way into the pleural space when there’s an open injury in your chest wall or a tear or rupture in your lung tissue, disrupting the pressure that keeps your lungs inflated.

Listen to pronunciation. (MEE-dee-uh-STY-nul PLOOR-uh) The thin membrane that lines the chest cavity in the area between the lungs.

Parietal pleura lines both thoracic cavities and may be designated by its location as costal, diaphragmatic, or mediastinal pleurae. Inferiorly, the parietal pleura extends deeply into the costodiaphragmatic recesses where costal and diaphragmatic pleura are in apposition.

The pleural cavity is the body cavity bounded by the parietal pleura, includes the lung, the hilar structures and the pleural space surrounding them, and varies in volume with breathing.

Pleural space. This is the area between the lungs and the chest wall. This space is lined on both sides by tissue called pleura.

Structure of the Pleurae

• Visceral pleura – covers the lungs.
• Parietal pleura – covers the internal surface of the thoracic cavity.

The inner pleura, called the visceral pleura, covers the surface of each lung and may dip between the lobes of the lung as fissures, and is formed by the invagination of lung buds into each thoracic sac during embryonic development.

Tension pneumothorax occurs anytime a disruption involves the visceral pleura, parietal pleura, or the tracheobronchial tree. This condition develops when injured tissue forms a one-way valve, allowing air inflow with inhalation into the pleural space and prohibiting air outflow.