The chest cavity contains the lungs, heart, major blood vessels, and other structures. It is bounded by the ribs, sternum, vertebral column, and diaphragm. The chest cavity is further divided into the pleural cavities and mediastinum. The mediastinum is the median partition between the lungs and contains the esophagus, trachea, thymus, and major blood vessels. Each lung is surrounded by a pleural membrane made of visceral and parietal layers that create a pleural cavity containing fluid.

1. Chest CavityBy:Dr Mohammed Faez

2. Chest CavityChest cavity enclosed by the 12 pairs of ribs and sternum anteriorly, vertebral column posteriorly and inferiorly by the diaphragm.

3. Chest CavityIt contains the lungs and bronchi, part of the esophagus and trachea, and the heart and major blood vessels.

4. Chest CavityThe chest cavity can be divided into a median partition, called the mediastinum, and the laterally placed pleurae and lungs.

5. Mediastinum(Interpleural Space)The mediastinum lies between the right and left pleurae in and near the median sagittal plane of the chest. It extends from the sternum in front to the vertebral column behind, and contains all the thoracic viscera excepting the lungs.Itextends superiorly to the thoracic outlet and the root of the neck and inferiorly to the diaphragm.

6. Mediastinum(Interpleural Space)it is divided into superior and inferiormediastinal regions by an imaginary plane(line) passing backwards horizontally from the angle of Louis (manubriosternal joint) to the vertebral column (T4/5 intervertebral disc).

7. Mediastinum(Interpleural Space)

8. MediastinumThe inferior mediastinum is subdivided into :Middle mediastinum Anterior mediastinum Posterior mediastinum

9. Superior MediastinumThe superior mediastinum is bounded in front by the manubriumsterni and behind by the first four thoracic vertebrae.

10. Superior Mediastinum ContentsRetrosternal:Great vessels branches ThymusPrevertebral:Trachea Esophagus Thoracic duct Sympathetic trunksVagus nerves

11. Inferior MediastinumThe inferior mediastinum is bounded in front by the body of the sternum and behind by the lower eight thoracic vertebrae .

12. Inferior MediastinumThe inferior mediastinum is subdivided into : • Anterior mediastinum: the region in front of the pericardium. • Middle mediastinum: consists of the pericardium and heart. • Posterior mediastinum: the region between the pericardium and vertebrae

13. Inferior Mediastinum ContentsAnterior mediastinum :Thymus Fat Lymph nodesMiddle mediastinum:PericardiumPhrenic nervesPericardiacophrenic artery Heart and great vessels

14. Inferior Mediastinum ContentsPosterior mediastinum:Esophagus Thoracic duct Aorta BranchesVagus nerves Sympathetic trunksAzygos system of veins

15. Pleurae (Pleural cavity)Pleurae is a thin covering serous membrane that protects the lungs.It is lining for the chest cavity.

16. Pleurae (Pleural cavity)Each pleura consists of two layers:Avisceral layer which is adherent to the lung and a parietal layer which lines the inner aspect of the chest wall, diaphragm and sides of the pericardium and mediastinum.

17. Pleurae (Pleural cavity)• The parietal and visceral layers of pleura are separated from one another by a slitlike space, called pleural cavity • The pleural cavity contains a small amount of pleural fluid which acts as a lubricant decreasing friction between the pleurae.

18. Pleurae (Pleural cavity)

19. Pleurae (The parietal layer)The costal pleura lines the inner surfaces of the ribs, the costal cartilages, the intercostal spaces, the sides of the vertebral bodies, and the back of the sternum

20. Pleurae (The parietal layer)The diaphragmatic pleura covers the thoracic surface of the diaphragmThe mediastinal pleura covers and forms the lateral boundary of the mediastinum

21. Pleurae Blood Supply Visceral pleura--- Artery supplied by bronchial and pulmonary arterial systems. The parietal pleura--- Artery supply is from various systemic arterial supply the chest wall, diaphragm, and mediastinum.

22. Pleurae venous drainage Visceral pleura--- Veins drain is pulmonary vein.The parietal pleura--- Vein is to the superior vena cava.

23. Pleurae Nerve Supply The parietal pleura is sensitive to pain, temperature, touch, and pressureThe parietal pleura is innervated by both somatic and sympathetic and parasympathetic fiber via the intercostal nerve.

24. Pleurae Nerve Supply The parietal pleura is supplied as follows:The costal pleura is segmentally supplied by the intercostal nerves.The mediastinal pleura is supplied by the phrenic nerve.The diaphragmatic pleura is supplied over the domes by the phrenic nerve and around the periphery by the lower six intercostal nerves.

25. Pleurae Nerve Supply The visceral pleura covering the lungs is sensitive to stretch but is insensitive to common sensations such as pain and touch.It receives an autonomic nerve supply from the pulmonary plexus.

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