142 Anatomy Applied to Medicine and Swgery. 



line at the level of the eighth rib, the normal resonance be- 

 comes tympanitic, because of the underlying stomach and 

 intestine. On the back the note is resonant, from the 

 apex of the lung downwards, until the level of the tenth 

 dorsal spine is reached, at which level, hepatic dullness is 

 evident on the right side and spleno-renal dullness on the 

 left side. 



Cardiac Neuroses. Nerves of the Heart. 

 The heart is controlled by intracardiac nerves situated in 

 its walls, and by extracardiac nerves, which are external to 

 the heart and are derived from the superficial and the deep 

 cardiac plexuses. These plexuses are situated above the 

 heart, the superficial one lying on the anterior 

 surface of the right pulmonary artery, below the 

 arch of the aorta, whereas, the deep one is found behind 

 the arch of the aorta, and, between it, and the bifurcation 

 of the trachea. The superficial plexus is formed by the left 

 Superior cardiac branch of the sympathetic, and the left 

 inferior cervical cardiac branch of the pneumogastric 

 along with branches from the deep plexus. The remain- 

 ing cardiac branches from both the cervical sympathetic 

 and the pneumogastric, go to the deep cardiac plexus. 

 The branches of distribution from these plexuses consti- 

 tute the anterior and the posterior coronary and the an- 

 terior and the posterior pulmonary plexuses. 



In angina pectoris a prominent symptom, in 

 addition to the fear of impending death, is pain 

 of an excruciating character. This pain may be due to 

 a spasm of the muscular structure of the heart 

 from defective nutrition, the result of an atheromatous 

 condition of the coronary arteries, or it may depend on 

 some primary disturbance of the cardiac plexuses. The 

 pain is frequently transmitted to the arm, occasionally to 

 the side of the neck and rarely to the face. The nervous 



