DISTRIBUTION OF THE PNEUMOGASTRICS 535 



clavian artery and has essentially the same course and distribution as 

 on the left side, except that it is smaller and has fewer filaments of 

 distribution. 



The important physiological point connected with the anatomy of 

 the recurrent laryngeals is that they animate all the intrinsic muscles 

 of the larynx except the crico-thyroid. Experiments have shown that 

 these nerves contain a large number of motor filaments derived from the 

 spinal accessory. 



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 

 sympathetic. The thoracic cardiac branches are given off from the 

 pneumogastrics 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 cardiac branches, send a few filaments to the trachea and 

 then form a plexus that surrounds the bronchial tubes and follows the 

 bronchial tree to its terminations in the air-cells. The posterior pulmo- 

 nary branches are larger and greater in number than the anterior. They 

 communicate freely with sympathetic 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 pos- 

 terior portion of the trachea, a few pass to the muscular 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 ramifica- 

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

 anterior branches. The pulmonary branches are distributed to the 

 mucous membrane and not to the walls of the bloodvessels. 



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 oesophageal 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 on 

 the two sides. 



On 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 



