pe 
PAR VAGUM. 387 
branches of the superior laryngeal of the 
opposite side, and with the arytenoid branch 
of the recurrent; and occasionally a filament 
perforates the arytenoid cartilage to reach the 
inner surface of the larynx. 
Vascular and cardiac branches.—The vagus 
in its passage along the neck sends off directly 
from its trunk several filaments, which throw 
themselves into the arterial nervous plexuses sur- 
rounding the carotid arteries and their branches ; 
and also others which pass downwards and 
join themselves, either directly or indirectly, to 
the cardiac plexus. These branches are very 
variable in their number, size, and origin, so 
that it is impossible to give any description of 
them which will be found generally applicable, 
and they commonly differ on the two sides in 
the same individual. 
Vascular branches (rami vasculares).— 
Several small branches arise from the trunk of 
the vagus between the origin of the superior 
laryngeal nerve, and about a line or so below 
the level of the bifurcation of the common 
carotid, and chiefly pass upon the carotid 
arteries and their branches. Valentin* has 
divided these into— 
1. Rami carotici, consisting of two or three 
larger and some smaller twigs, coming off 
from the vagus near the origin of the superior 
laryngeal and also from the commencement of 
the superior laryngeal. They run inwards and 
forwards upon the internal carotid. 
2. Ramus ad divisionem arterie carotidis is 
principally distributed upon the common carotid 
at its bifurcation. 
3. Rami vasculares posteriores et interni are 
generally three in number, come from that part 
of the trunk of the vagus on a level with the 
bifurcation of the common carotid, and run 
principally, as their name implies, to the 
nervous plexus on the posterior and inner part 
of the large neighbouring arteries. 
4. Rami vasculares anteriores et interni 
spring from the trunk of the vagus a very little 
below the origin of the last, run to the outer 
side of the common carotid, and assist with 
‘some of the other branches of the vagus and 
sympathetic in forming a nervous network on 
the outer and anterior side of this artery, while 
one or more twigs proceed downwards to join 
the superior cardiac nerve of the vagus. 
Cardiac nerves.—Two or three cardiac bran- 
ches come from the inner side of the vagus at 
some little distance from each other; the upper 
of these generally arises a little below the bifur- 
cation of the common carotid. These bran- 
ches proceed downwards and inwards, commu- 
nicate freely with each other, send some filaments 
upon the surface of the common carotid artery, 
anastomose freely with the cardiac branches of 
the superior and middle cervical ganglia of the 
sympathetic and with the recurrent, pass chiefly 
in front of the large arteries at the root of the 
_ neck, and terminate in the upper part of the 
cardiac plexus of nerves. Frequently, more 
especially when the upper cardiac branches 
are small, or when some of them are want- 
* Op. cit. 
ing, we \find a pretty large cardiac branch 
arising fromthe vagus about the upper part of 
the lower third of the neck, and passing down- 
wards, on the right side in front of the subcla- 
vian, on the left in front of the arch of the 
aorta, it throws itself into the upper part of the 
cardiac plexus. Two or more branches also 
leave the trunk of the vagus as it passes the 
subclavian on the right and the arch of the aorta 
on the left side, pass inwards and throw them- 
selves partly into the cardiac plexus and partly 
into the anterior bronchial plexus. 
Inferior laryngeal or recurrent branch.— 
( Ramus laryngeus inferior seu recurrens.) On 
the right side the recurrent arises from the vagus 
as it is passing over the anterior surface of the 
subclavian artery, while on the left side it is 
sent off from the vagus, generally from its inner 
side, as it is crossing the anterior surface of the 
transverse portion of the arch of the aorta. On 
the right side it hooks round the subclavian on 
the inner side of the scalenus anticus muscle, 
and passing upwards and inwards, first below 
the subclavian artery and then below the com- 
mon carotid, it reaches the right side of the 
trachea. On the left side it hooks round the 
arch of the aorta and obliterated ductus arte- 
riosus, and passing upwards and inwards below 
the aorta, the left subclavian at its origin, and 
the left common carotid, it reaches the left side 
of the trachea. The recurrent soon after its 
origin generally receives one or two additional 
twigs from the trunk of the vagus. Immedi- 
ately after it leaves the trunk of the vagus, it 
anastomoses freely with branches of the sympa- 
thetic, chiefly with the internal branches of the 
two inferior cervical and first dorsal ganglia of 
the sympathetic,—and while the right sends 
some twigs upon the outer surface of the sub- 
clavian artery, the left sends some upon the 
surface of the aorta. It also throws several 
twigs into the cardiac, tracheal, and bronchial 
plexuses. The left sends some twigs to the 
tracheal plexus, while the corresponding twigs 
of the right side come from the trunk of the 
vagus. The two recurrents then proceed up- 
wards along the sides of the trachea towards 
the larynx,—the left resting upon the anterior 
surface of the esophagus,—and are both co- 
vered by the sterno-hyoid and sterno-thyroid 
muscles. In this part of the course of the re- 
current it generally receives communicating 
twigs from the cardiac branches of the superior 
and middle cervical and sympathetic ganglia, 
and it also anastomoses with some of the upper 
cervical cardiac branches of the vagus. It also 
sends several twigs to the cesophagus and tra- 
chea, (esophageal and tracheal twigs of the 
recurrent, ) some of which perforate the fibrous 
membrane between the cartilaginous rings of 
the trachea, and reach its mucous surface, while 
others are distributed among the muscular 
fibres which complete the cartilaginous rings 
behind. As it approaches the larynx it sends a 
twig upwards and forwards, which anastomoses 
with a descending twig of the external branch 
of the superior laryngeal; and it gives 
some filaments to the thyroid body, to 
the mucous membrane of the lower part of 
