PNEUMOGASTRIC NERVE. 577 



The cervical cardiac branches, two or three in number, arise from the 

 pneumogastrics at different points in the cervical portion, and pass to the 

 cardiac plexus, which is formed in great part of filaments from the sympa- 

 thetic. The thoracic cardiac branches are given off from the pneumogas- 

 trics, below the origin of the inferior laryngeals, and join the cardiac plexus. 



The anterior pulmonary branches are few and delicate as compared with 

 the posterior branches. They are given off below the origin of the thoracic car- 

 diac branches, send a few filaments to the trachea, and then form a plexus 

 which surrounds the bronchial tubes and follows the bronchial tree to its ter- 

 minations in the air-cells. The posterior pulmonary branches are larger and 

 more abundant than the anterior. They communicate freely with sympa- 

 thetic filaments from the upper three or four thoracic ganglia and then form 

 the great posterior pulmonary plexus. From this plexus a few filaments go 

 to the inferior and posterior portion of the trachea, a few pass to the mus- 

 cular tissue and mucous membrane of the middle portion of the oesophagus, 

 and a few are sent to the posterior and superior portion of the pericardium. 

 The plexus then surrounds the bronchial tree and passes with its ramifications 

 to the pulmonary tissue, like the corresponding filaments of the anterior 

 branches. The pulmonary branches are distributed to the mucous mem- 

 brane, and not to the walls of the blood-vessels. 



The oesophageal branches take their origin from the pneumogastrics, 

 above and below the pulmonary branches. These branches from the two 

 sides join to form the cesophageal plexus, their filaments of distribution 

 going to the muscular tissue and the mucous membrane of the lower third of 

 the oesophagus. 



The abdominal branches are quite different in their distribution upon 

 the two sides. 



Upon the left side the nerve, which is here anterior to the cardiac 

 opening of the stomach, immediately after its passage by the side of the 

 oesophagus into the abdomen, divides into a number of branches, which are 

 distributed to the muscular walls and the mucous membrane of the stomach. 

 As the branches pass from the lesser curvature, they take a downward direc- 

 tion and go to the liver, and with another branch running between the folds 

 of the gastro-hepatic omentum, they follow the course of the portal vein in the 

 hepatic substance. The branches of this nerve anastomose with the nerve of 

 the right suie and with the sympathetic. 



The right pneumogastric, situated posteriorly, at the oesophageal open- 

 ing of the diaphragm, sends a few filaments to the muscular coat and the 

 mucous membrane of the stomach, passes backward and is distributed to the 

 liver, spleen, kidneys, suprarenal capsules and finally to the whole of the 

 small intestine (Kollmann). The anatomical researches by Kollmann (1860) 

 have been fully confirmed by physiological experiments. Before the nerves 

 pass to the intestines, there is a free anastomosis and interchange of fila- 

 ments between the right and the left pneumogastric. 



General Properties of the Roots of Origin of the Pneumogastrics. The 

 sensibility of the pneumogastrics in the neck, while it is dull as compared 



