What Is the Precordium?

The serous membrane lining the inner surface of the chest wall and the surface of the lungs is divided into two parts, the wall layer and the visceral layer. The closed space between the two layers is called the pleural cavity. It can be divided into four parts according to the position of the pleural wall: the top of the pleura is the part that protrudes from the upper mouth of the rib cage; the rib pleura is the part lining the inner surface of the chest wall; the pleura is the pleura covering the iliac crest; the mediastinal pleura is the mediastinal organ Surface pleura; parietal pleura parts move between each other, forming crypts in some parts and the lung margins do not extend into them. These crypts are called pleural sinuses. The sacrocostal sinus is formed at the turning point of the costal pleura and the iliac pleura. It is the lowest point of the pleural cavity, where exudate accumulates first during pleurisy. Visceral pleura covers the surface of the lung and extends into the interlobular fissure, which is closely connected to the lung parenchyma.

The serous membrane lining the inner surface of the chest wall and the surface of the lungs is divided into two parts, the wall layer and the visceral layer. The closed space between the two layers is called the pleural cavity. It can be divided into four parts according to the position of the pleural wall: the top of the pleura is the part that protrudes from the upper mouth of the rib cage; the rib pleura is the part lining the inner surface of the chest wall; the pleura is the pleura covering the iliac crest; the mediastinal pleura is the mediastinal organ Surface pleura; parietal pleura parts move between each other, forming crypts in some parts and the lung margins do not extend into them. These crypts are called pleural sinuses. The sacrocostal sinus is formed at the turning point of the costal pleura and the iliac pleura. It is the lowest point of the pleural cavity, where exudate accumulates first during pleurisy. Visceral pleura covers the surface of the lung and extends into the interlobular fissure, which is closely connected to the lung parenchyma.

Chinese name

pleura

Foreign name

pleura

Latin name

Pleuratus

Nature

Thin film

Classification

Dirty pleura

Pinyin

xing mó

1 Anatomy of pleura 1, pleura:

The pleura is a thin, smooth serosa. The visceral layer covering the surface of the lung is called visceral pleura, which is tightly bound to the lung parenchyma and folds into the fissure. The pleura that covers the inner surface of the chest and on both sides of the mediastinum is called the pleura. The two parts continue to fold back and forth at the root of the lung, forming a left and right fully enclosed latent cavity called the pleural cavity. There is negative pressure in the cavity, so the viscera and wall pleura are closely attached. When breathing, the lungs can expand or retract with the movement of the chest wall and diaphragm. There is a little serous fluid in the pleural cavity, which can reduce the friction between the viscera and the wall.

Wall pleura: Wall pleura has different names depending on the lining site, namely pleural apex, costal pleura, diaphragm pleura, and mediastinal pleura. The pleural apex (cervicopleura) is close to the front of the lung apex, and its highest point is located approximately 2.5cm above the inner 1/3 of the clavicle (3 to 4cm above the first rib), and the rear does not exceed the first rib. The top of the cervical pleura is often enhanced by the pleura and the small oblique muscle. The pleura is formed by the thickening of the intrathoracic fascia that stretches from the anterior edge of the transverse process of the seventh cervical vertebra to the inner edge of the first costal. It is not constant and only exists in about 2/3 of the people on one side. It starts from the anterior margin of the seventh cervical vertebra and ends at the subclavian artery sulcus of the first costal margin and the upper pleura. Muscle contraction can increase the membrane. Tension. The rib pleura is attached to the inner surface of the chest wall by loose connective tissue, which is easy to peel off. pleura is tightly covered on the top of , and it is not easy to peel off. Mediastinal pleura is a pleura that covers all organs between the two lungs. The pleura that surrounds the lung root and the ligament forming the lung migrates to the lung pleura (dirty pleura). Between the lungs, it continues down to the iliac pleura, which is the lung ligament. There is no lung root structure between the front and back layers. Some authors believe that when the root of the lungs descends with the diaphragm or the blood flow of the pulmonary veins increases, the pulmonary ligaments are stretched, which can provide space for the roots of the lungs to move down or the pulmonary veins to expand.

Some parts of the pleural cavity are not filled with lungs, but leave a certain gap, called the pleural crypt (pleural sinus), which is located at the turning point of the adjacent wall of the pleura. The costal pleural and pleural pleural reflex transition is called the costal crypt recess (costal sacral sinus). It is the largest and cannot be completely filled by the lungs during deep inhalation. Its depth can change due to breathing. In the upright position, because of its lowest position, pleural effusion often gathers here. The left pleural pleura migrates to the left mediastinal pleura, forming a costal mediastinal recess at the cardiac notch equivalent to the lung. The lungs are not filled during inhalation, only the pleura is separated between the pericardium and the chest wall. In addition, because the apical process was to the left, the left sacroiliac pleura and the mediastinal pleura migrated at the reflex, and there was still a small sacral mediastinal recess (condylar mediastinal sinus).

Anterior boundary of pleural body surface projection (costal mediastinum reflex line): starting from the back of the sternoclavicular joints on both sides, upwards, continuing with the cervical pleura at the inner edge of the first rib; downwards to the rear of the sternum angle, in the median sagittal plane Move towards each other until the 4th rib cartilage, and the sides are separated again. The person on the left side is inclined outward, and passes obliquely through the 4th intercostal space, the 5th intercostal space, and the intercostal space to the 6th intercostal cartilage. According to Chinese data, 42% of the left anterior border of the pleura is often located behind the sternum and does not exceed the left sternal line. Therefore, a pericardial puncture along the left sternal line in the fifth intercostal space may break the pleura. The right side continues to descend; the lower boundary is continued behind the sword-thoracic combination, and the left and right pleural anterior boundaries are not completely closed, leaving two triangular gaps. Above the sternum angle, it is called the upper interpleural region, which contains the thymus and fat. Below the costal cartilage, it is called the lower interpleural area (pericardial area), where the pericardium is directly attached to the chest wall, which is called the bare pericardial area. Lower pleura (costal fold reverse line): The left side begins behind the 6th costal cartilage, and the right side begins at the level of the flat sword-thoracic junction. After that, the two sides are basically the same; they all pass through four points, namely the intersection of the midline of the clavicle and the 8th rib, the intersection of the midaxillary line and the 10th rib, the intersection of the scapular line and the 11th rib, and the intersection of the outer edge of the iliac spine muscle and the 12th rib , Even lower; here is closely related to the kidney, has clinical significance: finally in the median sagittal plane approximately flat the 12th thoracic spinous process root. The lower pleura is at the sternum and the 12th rib, which can be lower than the lower pleura.

The left and right anterior boundaries of the pleura are mostly separated in the fetus. After birth, the anterior boundaries of the pleura are gradually approached and moved closer to each other. In the elderly, the anterior boundaries are mostly overlapping.

Blood vessels, lymph and nerves: Visceral pleura: Arteries are supplied by the bronchial and pulmonary arteries. The veins accompany the arteries of the same name. Lymph is injected into hilar lymph nodes. Nerves come from the pulmonary plexus. Mural pleura: Arteries are supplied by the bronchial artery, internal thoracic artery, intercostal artery, and superior iliac artery. The veins accompany the arteries of the same name. Lymphatic drainage: the lymph at the top of the pleura flows into the supraclavicular lymph nodes; the rest is injected into the parasternal and posterior intercostal lymph nodes, and the lymphatics of the iliac pleura and mediastinal pleura are drained to the mediastinal lymph nodes; the iliac pleural Lateral aortic lymph nodes. Nerves: Intercostal nerves are distributed in the costal pleura and the iliac pleura, and the sacral nerves are distributed in the mediastinal pleura and the central part of the sacral pleura. The parietal pleura, especially the costal pleura, is sensitive to pain and can cause significant pain when the pleura is inflamed.