568 
constitutes, in lean subjects, a manifest and 
resisting lamina, yet, in those of an opposite 
character, it is rendered indistinet by the pre- 
dominant adipose tissue which oceupies its 
areole. Along the side of the neck, from the 
clavicle to the jaw, these layers are kept asun- 
der by the platysma myoides, which adds, as 
it were, a third lamina to the subcutaneous ex- 
pansion; but beth in front and behind, where 
the muscle ceases, they are in close relation, 
and constitute a single covering to those regions 
of the neck. The deep layer of this fascia is 
traversed by the cutaneous nerves and vessels, 
including the external jugular vein. 
2. The cervical fuscia is a proper aponeu- 
rotic investment of this region, and corresponds 
in its general characters to the fibrous sheath- 
ings of the limbs, Like these, it not only 
forms a general, compressive, and modelling 
cincture for the part, but, by various secondary 
sputng®, furnishes dissepiments which isolate 
the different organs, and allot to each its proper 
sheath or fascial chamber. It may be briefly, 
but insufficiently, described as originating from 
a kind of linea alba, or mesial commissure in 
front, and in its backward course to the spinous 
processes furnishing a separate investment to 
every organ which it encounters, and attaching 
itself, both below and above, to the chief bony 
eminences which present themselves. (A sec- 
tion of it, as it thus cellu/ates tlie neck, is re- 
presented, with Bourgery’s almost invariable 
accuracy, in a lithograph, (vol. vi. pl. 10,) from 
which the accompanying woodcut is copied.) 
It requires, in at least many regions of the 
neck, a more particular description than this 
summary contains; and I shall accordingly 
proceed to consider such portions of it with 
some detail. The sterno-cleido-mustoideus is 
ensheathed through its whole extent; the fascia, 
on reaching its anterior edge, is bi-laminated, - 
encloses the muscle, and becomes again single 
at its posterior border. When this sheath is 
laid open by removing its anterior wall, and the 
muscle carefully everted from its prismatic cell, 
it will be seen that the posterior lamina is of 
greater strength than the removed anterior one ; 
and this surface is the one from which the dis- 
sector may most conveniently trace the further 
spread of the membrane. Le will find that 
the cervical fascia (of which the portion cover- 
ing the sterno-cleido-mastoideus is but a se- 
condary slip) extends itself from behind that 
muscle in all directions; inwardly to the me- 
sial line,—outwardly to the trapezius,—up- 
wardly to the jaw,—downwardly to the cla- 
vicle. a. Traced inwardly, its arrangement 
differs in the upper and lower parts of the 
neck: 1. in that below the os hyoides a su- 
rficial lamina covers the subhyoid muscles, 
oins its fellow in the median line, and is fixed 
low to the interclavicular notch of the ster- 
num; a second, thin process divides the sterno- 
thyroid from the sterno-hyoid muscle; a third, 
stronger one, passing between the sterno-thy- 
roid and air-tube, covers this latter organ and 
the thyroid body, is attached below to the inner 
surface of the manubrium sterni, internally joins 
the layer from the opposite side, and helps with 
NECK. 
it to forma raphe, reaching from the os hyoides 
to the actin notch. Previously to the divi- 
sions here mentioned, the fascia encloses the 
flat tendon and anterior belly of the omo-hyoid — 
muscle ; and in a line, which will presently be 
more particularly indicated, covers the carotid — 
artery, jugular vein, and nervus vagus. Just 
external to these parts, along the outer edg 
the jugular vein, it detaches a delicate process 
which behind the vessels, separating 
them from the sympathetic nerve, and is con- 
tinued inwardly to join its fellow from the 
opposite side, as a cellular clothing to th 
esophagus. 2. Above the os hyoides, th 
arrangement of the fascia is simpler; coverin 
the mylo-hyoid and submaxillary gland, r 
inclosing the anterior belly of the dig rie, i 
is fixed to the lower er of the symphysis 
and hence to a mesial raphe as far as the ¢ 
hyoides. It has some deep connexions, to wl 
1 shall return directly; and, to the sheath of 
great cervical vessels it P the sai e 
lations as below, its process lo 
itself on the pharynx. 6. Traced upwardly, 
fascia is seen to split on the inferior edge of 
digastric muscle; the su ial lamina is 
tached, behind, to the mastoid process, 
front, joining the part last described, t 
lower edge of the jaw, > intermediz 
ascends upon the id gland, which it 
vests ; shia deel 0 is fixed to the sty 
process of the temporal bone, and gives or 
to a remarkable septal slip, (sometimes cal 
the stylo-maxillary ligament,) which, just - 
front of the posterior belly of the digastric, pass 
outwardly, is inserted into the deep surface 
the superficial lamina and into the angle of | 
jaw, so serving to separate the space, circu 
scribed by the digastric muscle, into two pal 
and isolating the parotid gland, which ocew 
the posterior of these, from the submaxillai 
which is situated m the anterior one. Furthe 
this deep layer (joined by a slip from the fase 
which covers the submaxillary gland and is: 
tached to the jaw) prolongs itself around WI 
ton’s duct, between the mylo-hyoid and hy 
glossal muscles, and likewise furnishes oris 
to the investing cellular tissue of the phary 
c. Below, the cervical fascia attaches it 
around the insertions of the muscles, whi 
incloses, viz. towards the median line to” 
notch of the sternum, and—with the sub-hj 
muscles—to the deep surface of the manul 
and to the cartilage of the first rib, and the 
the clavicle in its entire length, both ar 
and between the sterno-cleido-mastoid and 
pezius. In descending to the clavicle, 1 
sheathes the posterior belly of the omo-hy 
and a firm process of it, folded aroun 
muscle and directed backward to the 
anguli scapule, is infixed along the su 
costa of that bone, and circumseribes th 
called omo-hyoid space. d. Traced oulwa 
and buckwardly the fascia covers in the i 
val between the trapezius and sterno-maste 
(posterior triangle) from the clavicle to the 
ciput, and, on arriving at the anterior edgi 
the trapezius, splits to enclose it. The fur 
mi 
distribution of it, in this direction, is im 
