NECK. 
approaches the root of the neck than in adult 
growth, and, as also the branches arising from 
it, may more easily be endangered in trache- 
otomy and other operations in the neighbour- 
hood. Its length is somewhat above an inch : 
its direction obliquely upward and outward, 
toward the sterno-clavicular joint, opposite to 
which it divides. In this course it corres- 
ponds, behind, to the trachea,—in front to the 
sternum, from which the remains of the thy- 
mus gland, the origin of the sterno-hyoid and 
sterno-thyroid muscles, and (close to its origin) 
the transverse crossing of the left vena inno- 
minata separate it,—externally, to its accom- 
yanying vein, and, mediately, to the pleura,— 
internally, to the left carotid from which it is 
separated by a triangular interval in which the 
thymus, or its remnant, lies upon the trachea. 
The frequency of its undue extension be- 
_ yond the precise limit assigned to it, and con- 
_ Sequent appearance in the sub-hyoid region of 
the neck, together with the fact of its often 
furnishing a middle inferior thyroid artery, are 
contingencies never to be disregarded in ope- 
rations thereabout. , 
This artery has now been tied for cure of 
anevrism at least six times; unsuccessfully— 
it is true—but with such nearness to success 
_ a8 not to forbid cautious repetition.. The mode 
of procedure adopted by Dr. Mott consisted 
iM a transverse division of the skin, muscles, 
and fascie along the edge of the clavicle and 
_ Sternum,—in raising these, and taking the sub- 
clavian and carotid arteries (which he seems to 
have denuded to some extent) as guides to the 
innominata, in drawing the jugular vein, the 
Vagus, phrenic and recurrent nerves outwards, 
mm pressing the pleura carefully downwards 
the convexity of the needle, while he 
carried its point from below upwards around 
the vessel. —- 
6. The digastric space is bounded below by 
the curve of the digastric muscle, and extends 
above within the angle and horizontal ramus of 
the jaw, so that, if considered as a triangle, it 
may be described as having its base represented 
by the internal oblique (or myloid) ridge of 
the lower jaw, and an imaginary prolongation of 
this to the root of the mastoid process,—its an- 
terior border formed by the ascending belly of 
the digastric muscle,—its posterior by the de- 
scending fibres of the same; and its apex will 
obviously be at the point of their reflexion by 
the hyoid bone. The skin, the superficial fascia 
with the platysma, and the cervical aponeurosis, 
wall it in, and that part of the inferior maxilla 
which lies beneath the oblique line, to the ba- 
sial edge of which the fascia adheres, overhangs 
it; its deep surface is constituted by the mylo- 
hyoid muscle and by the side of the tongue and 
pharynx in front, by the vaginal and styloid 
processes of the temporal bone behind. A 
fibrous slip, reflected outwardly from the sty- 
loid process to the angle of the jaw, and to the 
deep surface of the aponeurosis, distinctly di- 
vides the digastric space into two parts. Of 
these, the posterior is the smaller; its vertical 
extent is to the temporo-maxillary articulation : 
backwards it is bounded by the auditory canal 
581 
and mastoid process; inwardly, by the vaginal 
plate, the styloid process and its quscles. In 
the anterior direction the border of the jaw, to- 
gether with the septum just described, are its 
limits: whence it seems, within the neck of the 
jaw, to prolong itself as an interspace between 
the attachments of the pterygoid muscles. 
Between the unyielding walls of this nar- 
row space, the parotid gland contracts itself 
into a wedge-like form, reaches in the one 
direction to the styloid process and is folded 
round it, in the other is prolonged with the max- 
illary vessels between the insertions of the 
pterygoidei. In its substance the external ca- 
rotid ascends to its terminal subdivision—the 
portio dura curves from the stylo-mastoid fora- 
men, and breaks into the lash of communicating 
branches, known as pes anserinus,—the roots of 
the external jugular vein unite to assume that 
name,—and junctions of the portio dura with the 
superficial temporal nerve, and with the auri- 
cular branch of the cervical plexus, are met 
with. Its remarkable impaction behind the 
jaw is probably designed for affecting its func- 
tion by the mechanical stimulus of the masti- 
catory movements. Its enlargement may in- 
conveniently hinder these motions, and, where 
accompanied by much induration, actually lock 
the jaw. The merely anatomical difficulties of 
extirpating the parotid gland have probably 
been somewhat over-rated ; but cases requiring 
the operation must be of exceeding rareness. 
Absorbent glands lie on many points of its sur- 
face, and in its substance ; their enlargement is 
frequent, and has been mistaken, in several 
instances, for an affection of the parotid itself. 
The arteries met with in this space are all 
branches of the external carotid: the occipital 
and auricular follow its posterior border, the 
latter usually traversing a part of the gland ; 
the temporal artery emerges at the upper, the 
transverse facial at the anterior edge of the pa- 
rotid, while from its deep portion the internal 
maxillary passes forward, within the neck of 
the jaw, toward the zygomatic fossa. 
The anterior division of the digastric space 
considerably exceeds the posterior in size: its 
vertical extent behind is from the curve of the 
digastric up to the outward surface of the buccal 
mucous membrane, where reflected from the 
molar alveoli to the side of the tongue ; but an- 
teriorly it seems to be limited by the lower sur- 
face of the mylo-hyoid muscle, and so to be 
shallower ; though, in reality, this is not the 
case, for the muscle referred to merely forms a 
partial septum, dividing the shallow and super- 
ficial part, just mentioned, from a deeper, sub- 
lingual portion of great importance. The ante- 
rior division of the digastric space may accord- 
ingly be considered as bounded above by the 
mucous membrane of the mouth in its reflexion 
from the oblique line of the jaw to the border 
of the tongue, in an extent reaching from the 
base of the coronoid process to the symphysis ; 
and, internally, by the side of the tongue, 
(presenting the muscular substance of the genio- 
hyoideus, genio-hyoglossus, hyoglossus, and 
stylo-glossus,) and by that of the pharynx. It 
is only in front that the mylo-hyoid muscle, as 
