THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The intercostal spaces are simply the spaces between the ribs. They separate the ribs and their costal cartilages from one another and allow smooth expansion of the cage during inspiration.

Detailed explanation-2: -The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs. The intercostal muscles and neck muscles help move the rib cage and thus assist in breathing.

Detailed explanation-3: -Rib Cage and Abdominal Motion During normal breathing, contraction of the major inspiratory muscle, the diaphragm, produces both rib cage expansion and a downward movement of the diaphragm. These movements cause the pressure around and in the lung to become negative relative to atmosphere.

Detailed explanation-4: -The costal cartilages are bars of hyaline cartilage that serve to prolong the ribs forward and contribute to the elasticity of the walls of the thorax. Costal cartilage is only found at the anterior ends of the ribs, providing medial extension.