PAR VAGUM. 
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 
Jarge branches upon the posterior surface of 
that tube, and also a few smaller ones upon the 
—, surface of the pulmonary bloodvessels. 
ese 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 esophageal 
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 esophagus, where each nerve 
divides into three or four chords upon the sur- 
face of the esophagus; 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 esophagus, 
with those of the opposite nerve, and thus form 
an extensive and open network upon the sur- 
face of the esophagus, called the inferior ceso- 
phageal plexus (plexus cesophageus thoracis 
inferior).* From these chords nervous fila- 
ments pass into the walls of the esophagus, 
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.t 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 wsophageal plexus, 
_ and op formed by the right vagus the right @so- 
phag US. 
_ t Wrisberg (Ludwig’s Scrip. Nerv. Min. Select. 
_ tom. iv. p. 59) says, that he has seen the nervous 
_ chords of both vagi unite into a single trunk on the 
esophagus, which again divided itself into two 
_ branches (right and left vagi) before passing 
_ through the diaphragm. 
889 
posterior surface of the esophagus, 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 cesophagus, 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.+ 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 pylorie 
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 
through 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 ceeliac plexus. Some 
of the filaments of the latter portion may be 
traced into the numerous plexuses surrounding 
the gastro-duodenalis 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 esophagus, 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. 
+ Valentin, oper. cit. s. 500. : 
$ Vide Swan’s Demonstrations of the Nerves of 
the Human Body, plate viii. 1830 
