Generally, it refers to the external circumference of the human chest. The length can be said to be inches or centimeters. Chest circumference is also divided into upper chest and lower chest. Bust is also another name for bra. It is a kind of underwear used by women. Also known as bra, bra or bra. Sometimes it is also called underwear in general. Its function is to cover and support the breast.
When measuring, the subject's body is upright and his arms hang down naturally. When measuring a minor female, the measurer places the tape horizontally on the lower corners of the two scapulae, and puts the front on the mastoid peak. Measure the circumference of the chest around one week. When measuring an adult female, the measurer places the tape horizontally at the lower corners of the two scapulas, and places the tape in front of the joint of the fourth rib and the sternum. Measure the circumference of the chest around the circumference. First measure the circumference of the chest at rest, then measure the circumference of the chest at inspiration, and finally measure the circumference of the chest at expiration.
The difference in chest circumference between deep inhalation and deep exhalation is called dyspnea, which can reflect the function of respiratory organs. Generally, the adult dyspnea is 6-8 cm. The dyspnea of regular exercisers can be more than 10 cm. During measurement, the subject should not shrug his shoulders. When exhaling, he should not bend his back. The average chest circumference at birth is about 32cm. It is 1.2cm smaller than the head circumference. At the age of 1, the chest circumference is equal to the head circumference. After the age of 1, the chest circumference should gradually exceed the head circumference. The growth curve of head circumference and chest circumference forms a cross. It refers to this crossing. Its time is related to children's nutrition and chest development. The crossing of poor development is delayed.