DISSECTION OF THE DOG 



45 



intermediate lobe, there is a broad groove for the oesophagus. The intermediate 

 lobe itself forms a prominent, pointed projection on the surface. Sometimes 

 the cardiac depression is crossed by a narrow, shallow groove caused by the 

 right phrenic nerve. 



The dorsal or obtuse border (margo obtusus) of the lung is adapted to the 

 channel formed by the ribs and the vertebrae, and consequently is thin at the 

 apex, but becomes thick and rounded towards the base of the organ. 



The ventral or acute border (margo aeutus) is much shorter and thin 





y Lob us - ~ ~^~. 

 cardiac us 



Lob us 

 =?" apicalis j? 



jft Apex pulmbfiis 



Fades diaphragmatic3~ 



Kar/go aeutus 



Fig. 18. — Medial surface of the left lung, a, Groove for aorta ; 6, groove for phrenic 

 nerve ; c, depression for heart. 1, Bronchial rami for apical and cardiac lobes ; 2, 

 bronchial ramus for diaphragmatic lobe ; 3, pulmonary artery ; 4, pulmonary vein of 

 apical lobe ; 5, pulmonary vein of cardiac lobe ; 6, pulmonary vein of diaphragmatic lobe. 



throughout. It occupies the narrow space (sinus costo-mediastinalis) between 

 the ribs and the mediastinal septum, and is notched for the accommodation of 

 the heart (incisura cardiaca). The cardiac notch is much deeper in the right 

 lung than it is in the left ; consequently more of the heart is uncovered by 

 lung on the right side of the chest than on the left. 



The apex (apex pulmonis) of the lung is free, blunt, and laterally flattened. 

 The base (basis pulmonis), being applied to the diaphragm, possesses a concave 

 surface (facies diaphragmatica) which slopes in a caudal and lateral direction. 



