The lung is protected by the ribs in the chest, and there are two groups of muscles between every two ribs, which are called intercostal internal muscle and intercostal external muscle respectively, collectively referred to as intercostal muscle. When inhaling, intercostal muscles contract; When exhaling, the intercostal muscles relax.
Diaphragm is a muscle fiber structure located between the thoracic cavity and abdominal cavity. It is surrounded by a muscular abdomen with aponeurosis in the center, which is also translated as diaphragm. It is an important respiratory muscle of the body, accounting for 60% ~ 80% of all respiratory muscle functions.
Diaphragm:
Extended data:
Composition and auxiliary mechanism of diaphragm;
1, which can be divided into three parts: the sternum bulges behind the xiphoid process and is weak; The ribs start from the inner surfaces of the six ribs; The waist starts from the front of the 2nd ~ 3rd lumbar vertebrae, and the 1 transverse process of the lumbar vertebrae.
2. The diaphragm has three holes: the aortic hole through which the aorta and thoracic duct pass; Esophageal hiatus, where esophagus and vagus nerve pass through esophageal hiatus; There is a hole in the vena cava through which the inferior vena cava and phrenic nerve pass. Diaphragmatic nerve is a kind of mixed nerve, which is composed of nerve fibers from neck 3 to 5, and then descends to diaphragm. The shallowest part from the skin below the outer edge of sternocleidomastoid muscle 1/3 is the best part to stimulate phrenic nerve with electric pulse skin electrode.
3. Exercise: Diaphragm is the main respiratory muscle, which is controlled by will. During contraction, the diaphragmatic apex descends to assist inhalation; During diastole, the diaphragmatic apex returns to its original position to help exhale. When the diaphragm and abdominal muscles contract at the same time, abdominal pressure is generated, which is helpful for defecation, urination, delivery and vomiting.
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