RESPIRATORY APPARATUS. 



125 



borders of the lungs which then lie close to the points of insertion 

 of the diaphragm. At the acme of inspiration the rounded, cone- 

 like form of the diaphragm becomes more pointed and its base 

 and apex approach each other, the ribs having been drawn for- 

 ward. By this drawing forward of the ribs the transverse diam- 

 eter of the thorax is increased and the base of the cone-like dia- 

 phragm broadened. 



Dorsal and ventral boundaries of the flel 

 Costal attachment of diaphram H. heart, d. 

 colon. 



of pulmonary pcirussion 



dorsal colon. 1. v. c. left ventral 



Accordingly, the lateral border of the lung" is continually 

 moving backward and forward, traveling a distance in the larger 

 animals of 1-2 hands breadth, and in the smaller ones from % to 1 

 hands breadth. On an average the posterior border of the lung 

 may be defined by a line which in the larger animals is the width 

 of a hand from the points of insertion of the diaphragm. In 

 small animals the distance is one-half this. 



The availableness of the lungs for clinical examination. 



Dorsally the area of percussion is defined by the thick muscles 

 of the back. This boundary to percussion, which varies with 

 the condition of the animal, is limited by a line drawn from the 



