the role of the intercostal muscles when breathing
Rating Newest Oldest. Best Answer: &nbsp The intercostal muscles are mainly involved in the mechanical aspect of breathing. There are three principal layers; the external intercostal muscles, which aid in quiet and forced inhalation.They originate on ribs 1-11 and have their insertion on ribs 2-12.The external intercostals are responsible for the elevation of the ribs, and expanding the transverse dimensions of the thoracic cavity.oth the external intercostal muscles and the intercondral elevate the ribs, thus increasing the width of the thoracic cavity, while the diaphragm contracts to increase the vertical dimensions of the thoracic cavity, and also aids in the elevation of the lower ribs.