The sternal portion lowers the costal cartilages, facilitating inhalation by growing the chest cavity.The diaphragm is a muscle that helps you breathe. It sits less than your lungs and separates your upper body cavity from your abdomen.Ho?t ??ng c?a nó ???c th?c Hello?n thông qua liên k?t c? h?c ??n gi?n c?a piston, tr?c ti?p g?n vào màng ng?n