PAR VAGUM. 



889 



surface of the pulmonary veins and branches of 

 the trunk of the pulmonary artery, and anasto- 

 mose with branches from the inferior part of 

 the cardiac plexus prolonged upon these ves- 

 sels. Other branches proceed downwards and 

 inwards upon the anterior surface of the bron- 

 chii, and anastomose with the descending 

 branches of the anterior and inferior tracheal 

 plexus, with the nervous filaments accompany- 

 ing the pulmonary bloodvessels, and with some 

 branches direct from the sympathetic to form 

 the anterior pulmonary plexus (plexus pulmo- 

 nalis anterior). A few twigs also proceed from 

 this portion of the vagus into the anterior me- 

 diastinum, and are chiefly distributed in the 

 thymus gland. As the trunk of the vagus passes 

 behind the bronchus it sends off several pretty 

 large branches upon the posterior surface of 

 that tube, and also a few smaller ones upon the 

 posterior surface of the pulmonary bloodvessels. 

 These branches form a great part of the posterior 

 pulmonary plexus (plexus pulmonalis poste- 

 rior), and anastomose with twigs from the 

 posterior and inferior bronchial, with some fila- 

 ments from the superior thoracic cesophageal 

 and the anterior pulmonary plexuses. The 

 branches of the pulmonary plexuses, after send- 

 ing off some nervous filaments which run for 

 some distance below the pleura, (vide Reissei- 

 sen De Fabrica Pulmonum, 1822, tab. vi. 

 plate 2,) accompany the bronchial tubes and 

 bloodvessels into the interior of the lungs, and 

 follow the divisions and subdivisions of the 

 bronchial tubes. The two trunks of the vagi, 

 after leaving the lower edge of the bronchi, 

 soon reach the oesophagus, where each nerve 

 divides into three or four chords upon the sur- 

 face of the oesophagus ; those formed by the 

 subdivisions of the left vagus lying on its an- 

 terior and left side, those by the right vagus 

 on its posterior and right side. The chords of 

 the same nerve anastomose freely by large 

 branches, and also by smaller and less nume- 

 rous branches on both sides of the oesophagus, 

 with those of the opposite nerve, and thus form 

 an extensive and open network upon the sur- 

 face of the oesophagus, called the inferior ceso- 

 phageal plexus (plexus cesophageus thoracis 

 inferior).* From these chords nervous fila- 

 ments pass into the walls of the oesophagus, 

 and they also exchange some communicating 

 filaments with the sympathetic. Immediately 

 before the vagi pass through the cesophageal 

 opening of the diaphragm, the chords into 

 which each nerve has divided again reunite ; 

 those of the left nerve collecting into one trunk, 

 while those of the right frequently form two 

 branches which run close to each other.f As 

 they pass through the cesophageal opening, the 

 right nerve, or the larger, is placed on the 



* Some anatomists call that part of the plexus 

 formed by the left vagus the left cesophageal plexus, 

 and (hat formed by the right vagus the riyht ceso- 

 phageal plexus. 



t VVrisberg (Ludwig's Scrip. New. Min. Select, 

 torn. iv. p. 59) says, that he has seen the nervous 

 chords of both vagi unite into a single trunk on the 

 oesophagus, which again divided itself into two 

 branches (risht and left vagi) before passing 

 through the diaphragm. 



posterior surface of the oesophagus, and the 

 left, or the smaller, on its anterior surface.* 



Distribution of the vagus in the abdomen. 

 Left vagus. As it enters the abdomen it sends 

 some small branches upon the anterior surface 

 of the lower part of the oesophagus, some of 

 which enter the walls of that tube, others anas- 

 tomose with cesophageal twigs from the right 

 vagus, and others are prolonged downwards 

 upon the cardiac end of the stomach. As it 

 proceeds downwards over the cardiac surface of 

 the stomach it also passes towards the right 

 side and forms a curve, the convexity of which 

 looks to the left. From the convexity of this 

 curve several small branches run across the 

 anterior surface of the cardiac orifice and the 

 upper part of the large cul de sac of the sto- 

 mach, and some of these anastomose with 

 filaments from the left portion of the solar 

 plexus, and from the phrenic nerve. -f From 

 the concavity several small branches run up- 

 wards and to the right between the layers of 

 the smaller omentum to join the left hepatic 

 plexus.} The left vagus now divides itself into 

 several branches, which pass towards the pyloric 

 surface of the stomach, along the upper edge 

 of the anterior surface of the stomach, very 

 close to the smaller curvature of that organ, 

 and along the lower edge of the coronary artery 

 of the stomach, sending numerous filaments 

 into the nervous plexuses of the sympathetic 

 surrounding the coronary and superior pyloric 

 arteries, and also branches downwards over the 

 anterior surface of the stomach. These latter 

 branches, after running a greater or less distance 

 below the peritoneal covering of the stomach, 

 penetrate the muscular coat where some of 

 their filaments terminate, while others pass 

 tli rough it to reach the mucous coat. The few 

 branches of the left vagus which reach the 

 pyloric orifice are partly distributed upon the 

 walls of that portion of the organ, and partly 

 throw themselves into the coeliac plexus. Some 

 of the filaments of the latter portion may be 

 traced into the numerous plexuses surrounding 

 the gastro-dtiodenalis branch of the hepatic 

 artery, into the right hepatic plexus, and may 

 sometimes be followed as far as the artery of 

 the gall-bladder. The branches which leave 

 the left vagus as it lies on the anterior surface 

 of the lower part of the oesophagus, and cross 

 the anterior surface of the cardiac orifice of the 

 stomach, divide and subdivide below the peri- 

 toneum in a forked manner, and also anas- 

 tomose freely with each other, forming a kind 

 of plexus which has been termed the anterior 

 cardiac plexus of the stomach. As the branches 

 of the left vagus pass along the smaller curva- 

 ture of the stomach, they not only anastomose 

 freely with the plexuses of the superior coronary 

 and superior pyloric arteries, but with each 

 other, forming a plexus along the upper edge 

 of the anterior surface of the stomach, stretch- 

 ing from the cardiac to the pyloric orifice, 



* Wrisberg (opus cit. ) states, that the vagi send 

 a few filaments to the diaphragm. 



t Valentin, oper. cit. s. 500. 



J Vide Swan's Demonstrations of the Nerves of 

 the Human Body, plate viii. 1830. 



