External Respiration, 



8 9 



3. Left Auriculo-Ventricular Orifice 



4. Right Auriculo-Ventricular Orifice 



The heavy black line between the heart and the liver represents the diaphragm. 



1. Pulmonary Orifice 



2. Aortic Orifice 



Fig. 53. Front View of the Thorax. The Ribs and Breastbone are represented in 

 Relation to the Lungs, Heart, and other Internal Organs 



