884 
nold was the first who described the ramus 
auricularis in the human species. 
Passage of the vagus ee the neck to the 
origin of the inferior or recurrent larungeal 
branch —After the vagus emerges from the in- 
ferior aperture of the foramen lacerum poste- 
rius, it lies between the internal carotid artery 
and the internal jugular vein, the artery being 
internal and anterior, and at first separated a 
small distance from it, the vein being immedi- 
ately posterior and external. The glosso-pha- 
ryngeal is still placed on its anterior side, but 
soon leaves it and crosses the anterior surface 
of the internal carotid artery on its way to the 
root of the tongue. The spinal accessory is 
still on its posterior side, but a little above the 
transverse process of the atlas the external 
branch begins to diverge backwards and out- 
wards, and passes beneath the upper part of 
the internal jugular vein to reach the inner sur- 
face of the upper A of the sterno-cleido- 
mastoid muscle. e sympathetic nerve lies 
immediately posterior to it. The hypoglossal 
approximates its outer edge immediately below 
the foramen lacerum, gradually gets upon its 
anterior surface, is seen emerging from the 
angle left between it and the external branch of 
the accessory, where these nerves begin to sepa- 
rate, and opposite the transverse process of the 
atlas, or sometimes a little below this, it has 
crossed over its anterior edge, and proceeds 
forwards and inwards to reach the tongue. The 
hypoglossal, in crossing over the anterior sur- 
face of the vagus, is very closely bound to it by 
cellular tissue, and some small communicating 
branches pass between them. Some small 
communicating branches also pass between this 
portion of the vagus and the external branch of 
the spinal accessory, the superior ganglion of 
the sympathetic, the glosso-pharyngeal, and the 
nervous loop formed by the anterior branches 
of the first and second cervical nerves in front 
of the transverse process of the atlas. The 
vagus also in this part of its course generally 
sends a branch to join the descendens noni, 
and more rarely the descendens noni is almost 
entirely or altogether formed by this branch of 
the vagus.* All these nerves and bloodvessels 
in the upper of the neck are surrounded 
and connected together by cellular devoid of 
adipose tissue. The vagus, after joining itself 
to the internal carotid artery, accompanies it to 
the point of bifurcation of the common carotid, 
and then continues its course down the neck, 
enclosed in the same sheath with the common 
carotid and internal jugular vein, the artery 
being internal, and the vein external and also 
anterior. The nerve maintains the same rela- 
tion to these two vessels on both sides as far as 
the lower part of the neck, where on the right 
side the artery and vein diverge from each 
other, the artery passing inwards and the vein 
outwards, to join itself to the vena innominata ; 
while on, the left side the vein and artery have 
* Krause (Handboch der Menschlichen Anato- 
mie, S. 1 & 1063. Hannover, 1842) states 
that probably these strengthening filaments of the 
vagus furnish the cardiac branch of the descendens 
noni. 
PAR VAGUM. 
scarcely separated from each other, when the 
junction between the former and left subclavian 
vein takes place. On the right side the nerve 
is seen lying in the interval between the inter- 
nal jugular and the internal carotid, and while | 
crossing the anterior surface of the right sub- 
clavian artery nearly at right angles, it sends off 
the right inferior laryngeal or recurrent nerve, 
On the left side it passes downwards into the 
thorax, still lying close to the outer side of the 
leftcommon carotid ; but as it proceeds onwards, 
it crosses obliquely the left subclavian artery 
near its origin, and passing over the transverse 
portion of the arch of the aorta, it there gives 
off the left inferior laryngeal nerve. On both 
sides it passes into the thorax beneath the vena 
innominata.. 
The vagus, on emerging from the foramen 
lacerum, is near to the outer edge of the 
rectus capitis anticus minor muscle and in 
front of the rectus capitis lateralis; in its pas- 
sage down the neck it first crosses the anterior 
surface of the lateral part of the atlas, then 
proceeds along the anterior surface of the rectus 
capitis anticus major muscle, and lastly it de- 
scends upon the longus colli. In theu 
of its course it lies deep, and crosses 
neath the styloid process of the tem bone 
and stylo-pharyngeus muscle. In the middle — 
of the neck the two vagi nerves have approached — 
nearer to each other, and are much more su- 
perficial. In the lower part of the neck they 
are again placed deeper, and are covered by 
the sterno-hyoid, sterno-thyroid, and sterno- 
cleido-mastoid muscles. 
As the vagus emerges from the lower part 
eof the foramen lacerum, its fibres are ; 
somewhat loosely together, and are not 
enclosed in any dense and com neuri- 
lema, so that it is larger here at the 
lower part of the neck ; and when the cellular 
tissue surrounding it is removed, the outline of 
the superficial fibres can be readily traced. 
About half an inch below = lower of 
the superior ganglion it enlarges sti rey 
paalitn.tete shicaa rounded swelling, from nine 
lines to an inch in length, and extending from 
about the transverse process of the atlas to 
midway between the transverse processes of the 
second and third cervical vertebre (plerus ge 
gliformis nervi vagi, ganglion 
of Wutzer, ganglion trunci n. v. of ; 
ganglion inferiusn.u.) In the human specie 
though this swelling has a greyish colour, } 
its appearance is that of a plexus more than | 
a true ganglion ; and Valentin states* that 
has not yet obtained satisfactory evidence thi 
it contains the ganglionic nucleated glot 
without the presence of which there can be 
true ganglion, and he believes that the g 
* In many of the Mammalia this 
more circumscribed and less elongated than in | 
human species, and forms a very distinct and t 
ganglion. Bischoff (oper. cit, tab. ii.) has giv 
representations of it in the cat, fox, sow, mol 
and weasel; and Mr. E. Cook, (Guy’s Hos} 
Reports, vol. iis ps 311,) in the guinea-pig, 
and sheep. In all these animals it rap th 
part of the trunk of the vagus from which 
rior laryngeal nerve arises. 
