Knowledge about breast development

Breast development should be an issue of concern to many people. Whether it is a girl or a boy, they should have a preliminary understanding of this knowledge. Of course, some people may think that this is a more private issue. In fact, it depends on how you look at this issue. From a health perspective, we need to study it carefully.

The upper boundary of the chest is the lower boundary of the neck, the lower boundary is the lower opening of the bony thorax, and the outside is the anterior and posterior edges of the deltoid muscle. It is the second largest body cavity part of the human body. This area is divided into two parts: the thoracic cavity and the contents of the thoracic cavity; the thoracic cavity is further divided into the chest wall and diaphragm; the chest wall is further divided into the anterior, lateral and posterior walls by the anterior and posterior axillary lines, among which the posterior wall is called the back and belongs to the spinal region; the contents of the thoracic cavity are further divided into the mediastinum in the middle and the lungs and pleura on both sides.

The boundaries of the chest, body surface landmarks and the division of chest landmark lines. The characteristics of the superficial and deep fascia of the chest wall, the distribution and communication relationship of the superficial veins, the distribution of cutaneous nerves, and the structure of the proper chest wall. The surface projection of the lung and pleural reflection line, the surface projection of the heart and great blood vessels and their clinical significance.

During inhalation, the main inspiratory muscles, the external intercostal muscles, contract, lifting the ribs and increasing the transverse and sagittal diameters of the thorax. The other main inspiratory muscle, the diaphragm, contracts, causing the diaphragmatic dome to descend and the vertical diameter of the chest cavity to increase. As a result, the chest cavity volume increases and the pleura and lungs expand accordingly. Therefore, any muscle that can lift the ribs can assist in inhalation, such as the upper limb muscles of the chest and the posterior superior serratus muscles, which are involved in deep inhalation activities. The pleura reduces friction during lung movement. During exhalation, the internal intercostal muscles contract and the effect of gravity causes the ribs to drop, reducing the transverse and sagittal diameters of the chest cavity. At the same time, the diaphragm relaxes, the diaphragmatic dome rises, the vertical diameter of the chest cavity decreases, and the lung volume decreases along with the chest cavity volume.

So everyone should know a little about this aspect. Many times, as long as you know some things, you will know what is best for your own healthy development. In this way, you may be much better than others. So for your own health, read more about this knowledge.