Flat chest: It refers to the thoracic shape with a flat thorax, and the anterior and posterior diameters are significantly reduced, often shorter than the left and right transverse diameters.
Flat thorax: it refers to the shape of the thorax with flat thorax. The anterior and posterior diameter is significantly reduced, often shorter than the left and right transverse diameter.
Flat chest: It refers to the chest shape with flat chest, and the front-back diameter is obviously reduced, often shorter than the left and right transverse diameters.