Structure of the chest, showing the framework of the bones which are connected together chiefly by muscles. It is important to understand the structure of the chest in order to understand how the movements of the chest are made in inspiration and expiration. The spinal column <em>b,b</em> is the grand pillar that supports this barrel-shaped framework. The ribs <em>c, c, c</em> are fastened very strongly by ligaments to the spinal column. They are 2 in number, 12 on each side and extend round towards the breast bone (sternum) <em>a</em> in front.

Structure of the Chest

Structure of the chest, showing the framework of the bones which are connected together chiefly by muscles.…

Diaphragm in the state of its greatest ascent in expiration; 2, muscles of the abdomen in action forcing the viscera and diaphragm upwards.

Diaphragm During Expiration

Diaphragm in the state of its greatest ascent in expiration; 2, muscles of the abdomen in action forcing…

Diaphragm of the diaphragm and it's placement in the chest. Let <em>a</em> represent the spinal column, <em>b</em> the front wall of the chest, <em>Cc</em> the cavity of the chest, and <em>Ca</em> the cavity of the abdomen. At <em>d</em> is represented the diaphragm. As you can see from the figure, as the fibers of the diaphragm are shortened the space in the chest increases which is what takes place during inspiration. On the contrary, during expiration the diaphragm is pushed upward as shown in this figure so the room in the chest is lessened and air is forced out.

The Diaphragm

Diaphragm of the diaphragm and it's placement in the chest. Let a represent the spinal column,…

Showing position for inspiration (top) and position for expiration (bottom).

Treatment of Suffocation

Showing position for inspiration (top) and position for expiration (bottom).

Orthodiagram of the thorax. The position of parts is shown in extreme inspiration; the position of the diaphragm and liver in expiration is also shown.

Orthodiagram of the Thorax

Orthodiagram of the thorax. The position of parts is shown in extreme inspiration; the position of the…