570 
the prolongation which it sends downward on 
the scaleni; and which partly fixes itself to the rib 
around the attachments of those muscles, partly 
extends itself, as a strong infundibulum on the 
brachial plexus and subclavian vessels. From 
this—their fascial sheath—an horizontal slip 
detaches itself and passes forward to the pos- 
terior surface of the clavicle, where it fixes 
itself by two lamine ; the upper of these is 
inserted just above the attachment of the sub- 
clavius muscle, while the lower is continued 
into the sheath which that muscle derives from 
the coraco-costal fascia. The horizontal pro- 
cess separates the cavity of the axilla from the 
lower triangle of the neck, and the vaginal 
prolongation, contracting as it descends, be- 
comes lost in the sheath of the axillary vessels. 
Finally, as these various layers of fascia at- 
tach themselves about the inlet of the thorax, 
(the sub-hyoid part of the cervical aponeurosis 
in front, and the pre-vertebral behind,) they 
are connected to one another and to the large 
vascular and mucous canals, which traverse 
that passage, by certain horizontal processes of 
fibrous membrane, which constitute together a 
kind of diaphragm, or cervico-thoracic septum. 
Viewed from below this would seem a vaulted 
membrane, overarching the tops of the pleu- 
re, and giving infundibular passage to the 
great arterial and venous trunks and to the 
trachea; viewed from above it would present 
the various deep implantations of the cervical 
fascia, and a surface without aperture or breach 
of continuity, prolonging itself in several di- 
rections round the canals, which it thus indi- 
rectly transmits. The obvious use of these ar- 
rangements is to supply adequate resistance to 
the atmospheric pressure, which, were it not 
borne off by the tension of these fascia, would 
at each inspiratory effort tend to flatten the 
trachea, or to rush through the upper strait of 
the thorax. Allan Burns, who in this country 
first drew attention to the importance of the 
cervical fascia, carefully illustrates its func- 
tions in health, and the inconveniences which 
accompany its destruction. (Op. cit.) 
III.—RectonaL DISTRIBUTION AND SUR- 
GICAL ANATOMY OF THE NECK. 
The posterior parts of the neck having been 
described in a previous article (see Back), the 
present will be restricted to an account of its 
anterior aspect. 
The cervical vertebre (by their bodies, inter- 
vening fibro-cartilaginous discs, and transverse 
processes), together with the anterior and la- 
teral vertebral muscles, already described, com- 
pose the skeleton and supporting fabric of this 
region; the anterior fibres of the trapezii, as 
they descend on either side to the inner edge of 
the acromio-clavicular arch, form its lateral 
boundaries ; the larynx and trachea (covered 
by their own extrinsic riband-like muscles, and 
partly covering the pharynx and cesophagus) 
separate the nearly symmetrical halves of the 
neck by constituting alonz its median line a 
marked columnar relief, in the recesses beside 
which lie the great cervical vessels; the base 
of the skull and the oblique line of the jaw are 
NECK. 
the upper limits of the region; the clav 
(just behind which the great vascular and ner- 
vous trunks of the upper extremity course 
bounds it below; the skin, the platysm 
myoides (in its cellular covering), and the ¢ 
vical a rosis are stretched across it as ge 
neral investments; while the last-named fast 
ensheathes the various parts by special pre 
cesses from its deeper surface. 
Thus, in general terms, the structure of fl 
neck may be described ; but, for the more pi 
cise and particular account, which the imp 
tance of its anatomy renders 
division of it into spaces of small ex 
convenient. The arrangement, which I prop 
following, differs but little from that usua 
adopted, and, perhaps, somewhat exceeds it 
precision. y 
The upper limits of the neck having t 
stated as the oblique line of the jaw 
base of the skull (which parts, as we si 
sently see, are brought into relation 
eitachanpats of the constrictor pharyng 
rior), our highest region has in that diret 
these parts for its boundary, and extends b 
as far as the curve of the muscle, from wh 
is named the digastric space. - ¥ 
A small space that can hardly be referr 
the digastric,—from which it is separated by 
vaginal process of the temporal bone, am 
attachments of fascia,—and which, from thei 
portance of its contents, deserves careful eo 
deration, is the posterior pharyn, 3 it 
closely beneath the base of the skull, (from 
vaginal process to the median line) be 
pharynx and spine, and includes the 
jugular, and condylic canals, and the 
traversing them. 
If now an oblique line be carried 
neck, from the sterno-clavicular artieu 
the tip of the mastoid process, it divides, 
diagonal, the remaining quadrilateral sui 
the neck into two triangles; an anterior 
having its apex at the sterno-clavicular 
and its base along the posterior bell 
the digastric muscle; a posterior one, ha 
its base at the inner two-thirds of the 
vicle,—its apex at the mastoid process, 
posterior side formed by the trapezius,— 
terior border defined by the imaginar 
which demarks it from the anterior tra 
The omo-hyoid muscle, in its reflected « 
crosses both these triangles, subdividing | 
and since the angle of its bend falls just 
line of their separation, and since it pr 
from behind the outer third of the clay 
the body of the hyoid bone, it acts as a 
j 
nece: 
er 
arx? 
diagonal in the neck, dividing each 
upper and a lower triangular space. 
four triangles will be described in deta 
since the sterno-mastoid (which is too 
stantial to be treated as a mere bow 
enters into all of them, and has to p 
relations of the extremest practical imp 
some separate, chiefly recapitulatory 
deration will be given to its relative anate 
Finally, to ensure for the organs of the me 
line the consideration — require (the use 
ness of which mainly depends on their be 
