NECK. 
of the scaleni, it would appear, instead of 
having, as its fellow has, a certain length of 
transverse course, to bend abruptly toward the 
arch of the aorta, becoming deeper and deeper; 
or, in other words, while the right subclavian 
has a considerable extent at its highest level, 
from the sterno-clavicular joint to the scalene 
space, the left has comparatively but a cul- 
minating point, to which it suddenly rises and 
from which it quickly sinks. Thus the nerves, 
which cross the course of the right, are nearly 
parallel to that of the lefi: and the relation of 
the jugular vein is similarly changed, while the 
_ Subelavian vein, having a longer course than 
‘on the right side, obliquely crosses the thoracic 
_ portion of its artery. 
_ The anatomy of the veins requires some sepa- 
_ rate notice: in crossing the scalenus anticus at 
‘itsinsertion, the subclavian vein is, on both sides, 
_ anterior to the artery, from which the tendon di- 
_ Vides it,and somewhat inferior to it; the jugudar 
_ vein in the upper part of the neck descends as 
already mentioned, beside the internal and com- 
“mon carotid arteries, to which it is external, 
“similarly on both sides. The union of these 
veins, however, to form the vene innominate 
differs in the following manner. On the right 
‘side, the jugular vein, inclining from its artery 
Ow, joins the subclavian on the insertion 
the scalenus anticus: the arrangement of 
@ important parts is such that they form 
together an elongated triangle, of which the 
| + id artery is the inner side, the jugular vein 
__ the outer, and the first stage of the subclavian 
_ the base, here crossed ata right angle by the 
: ‘pneumogastric nerve, (which reflects its recur- 
3 
wnt branch upward and inward behind the 
tery,) and more outwardly by the phrenic : 
this point of junction the innominata vein 
rans toward the pericardium on the pulmonic 
‘side of its artery, that is, externally to it and 
0n an inferior plane. On the opposite side the 
\ egelas vein, anticipating its ultimate destina- 
_ tion, obliquely bends toward the right side, 
_ Overlapping the carotid artery, in front of 
_ which it receives the subclavian vein by its 
side: the resulting vena innominata 
Sst runs almost transversely across the arch 
join its fellow at the right extremity of this. 
The vertebral vein opens into the innominata, 
i internally to the confluence which forms 
lat trunk. On the left side it crosses the sub- 
clavian artery: on the right side it is usually, 
though not always, behind it. 
_ The thoracic duct, mounting from the medi- 
astinum, passes behind the arch, emerges be- 
tween the carotid and subclavian arteries in 
the root of the neck, and, curving abruptly 
downwards, outwards, and forwards, crosses the 
latter artery and discharges its contents by a 
valvular opening into the subclavian vein close 
to the angle of its confluence with the jugular. 
_ The surgical relations of this region regard 
the subclavian artery and the operations which 
are practised on it. Of these the most usual 
is its nee on the outside of the scalene 
Fp ere lying upon the upper surface of 
the rib. An onion; eeok ert to the 
middle of the clavicle, through the skin, super- 
OO 
———EE 
———— 
579 
ficial fascia, and platysma, and through the 
strong single layer of cervical Serene 
which is fixed to the bone,—extending, if neces- 
sary, to the origin of the sterno-mastoid and to 
its sheath, with careful avoidance of the ex- 
ternal jugular vein, here bending round the 
outer edge of the muscle,-—opens a space, where- 
in loose cellular tissue alone veils the conti- 
nuation of the pre-vertebral fascia, which is 
prolonging itself from the scaleni around the 
subclavian vessels: a division of this lamina, 
as near as possible to the costal attachment of 
the scalenus anticus, completes the exposure 
of the artery, which is recognised by the finger, 
as it emerges from behind the tendon of that 
muscle, in immediate contact with the mb. 
The steps of the operation thus considered 
seem of no great difficulty, and are, in fact, 
so long as the parts retain their normal bear- 
ings, of extremely easy performance: the artery 
is at an inconsiderable depth; its relations are 
singularly definite and unembarrassed. But 
such is not their practical facility, under cir- 
cumstances which necessitate the operation. 
To tie the subclavian artery for axillary aneu- 
rism may be one of the most difficult opera- 
tions in surgery, involving extreme patience 
and much manual skill in him who undertakes 
it; for the disease, as it extends, not only fills 
the axilla, but encroaches on the neck, thrust- 
ing up the clavicle, and obliterating the in- 
terval between that bone and the omo-hyoid 
muscle. The operation might almost be com- 
pared to one of tying the axillary artery in its 
normal relations from above the clavicle. It 
lies at the bottom of a deep and narrow cavity, 
in which the operator must be guided entirely 
by the sense of touch, and can only apply this 
under the disadvantage of distance. The cir- 
cumstances of such a case are well given by 
the late Mr. Todd of Dublin,* who states 
that, “so much was the relation of parts al- 
tered by the magnitude of the tumour and 
consequent elevation of the clavicle, that the 
omo-hyoid was situated an inch below this 
bone, and it was found necessary to draw it 
up from its concealment, and to cut it across, 
that the subjacent parts might become acces- 
sible.” It must be under the influence of 
such changes that the aneurismal sac, by en- 
croaching on the very seat of the operation, 
becomes liable to injury, and may, as I have 
witnessed, be actually transfixed by the needle. 
The relation of the brachial plexus is com- 
monly such that it lies on a plane posterior to 
the artery, and for the greater part above it; 
occasionally, however, its last root passes in 
front of the vessel, and in the disguised con- 
dition of parts is not readily to be distin- 
guished from it; since the touch fails in its 
ordinary discrimination, where exercised with 
so much difficulty, and it is hardly practicable 
to apply the test of compression to the sup- 
posed arterial trunk, in the view of ascertain- 
ing its relation to the tumour, without un- 
intentionally extending the same pressure to 
the subjacent artery and mis-informing one’s- 
* Dublin Hospital Reports, vol. iii. 
2P2 
