740 
SURGERY. 
process is to be gradually pushed backward with the index 
finger of one hand, while the index and middle fingers of 
the other hand are to be applied to the front teeth, and the 
thumb to the basis of the anterior part of the jaw. At the 
same moment that the coronoid process is pushed back¬ 
wards, the front portion of the bone is to be raised and 
inclined forwards. When one end of the fracture is situated 
over the other, the two parts of the bone are to be pushed 
in opposite directions, and if this be skilfully done, the 
slightest pressure on the extremities of the fracture will suffice 
for placing them in contact. 
That the fracture is well reduced, may always be readily 
known by adverting to the evenness of the dental line, and 
that of the base of the jaw. 
The surfaces of the fracture having been placed in even 
contact, the jaw is to be covered with pasteboard, and the 
four-tailed bandage applied. It will also be necessary to 
counteract the action of muscles, between the lower jaw and 
os hyoides, by supporting the front portion of the bone with 
compresses placed under the bandage. 
According to Delpech, nothing is more essential for keep¬ 
ing the fragments in their right place, than applying betwixt 
the teeth of the upper and lower jaws a piece of cork, cut 
into a suitable shape, and with depressions for receiving the 
projections formed by the teeth. Without this apparatus, he 
says, the four-tailed bandage, the pasteboard, and even the 
plan of fastening the adjoining teeth together with wire, or 
catgut, will not have due effect. A similar piece of cork is 
also to be placed between the teeth on the opposite side, an 
interspace being left between the two portions sufficient 
to receive a small spoon, with which the patient is to be 
fed. 
The lower jaw is subject to only one species of disloca¬ 
tion, namely, that in which the condyles advance forwards 
over the eminentise articulares, and slip under the zygoma. 
Sometimes the luxation is confined to one side; but, in all 
common instances, both condyles are displaced. 
A very little consideration would inform a surgeon, duly 
acquainted with anatomy, that the condyles of the lower 
jaw could not be displaced backwards, under the prominence 
formed by the lower part of the meatus auditorius, unless 
the bone were raised considerably above its point of contact 
with the upper jaw. Nor could one condyle be displaced 
outwards, without the other being at the same time carried 
inwards, below the projection of the spinous process of the 
sphenoid bone. This is a movement, therefore, which may 
be regarded as impossible, because it could not take place 
without a fracture of the spinous process, and any blow, or 
cause at all calculated to produce this accident, would be 
much more likely to fracture the ramus, or body of the 
lower jaw-bone itself. 
With respect to the causes of a dislocation of the jaw, 
every thing that has a tendency to separate the upper and 
lower maxillae further from each other, than is natural, may 
occasion the accident. Thus, yawning, vomiting, laughing, 
and blows on the chin, may be considered as the most 
frequent causes of the displacement. 
When the lower jaw is dislocated by the action of the 
muscles, as in gaping, vomiting, laughing, &c., the muscles, 
which are inserted into the os hyoides first depress the bone, 
and, in proportion as this movement increases, the ptery- 
goideus externus acts, and draws the condyle and inter- 
articular cartilage forwards upon the eminentia articularis. 
The displacement now more readily follows, because in the 
above-mentioned circumstances, the pterygoideus externus 
contracts in a powerful spasmodic manner. 
When the lower jaw is dislocated, the bone is depressed 
and fixed in this position ; the dental arches are separated 
by a space of about an inch and an half. The upper and 
lower teeth no longer correspond : the lower incisores are 
placed too much forwards; and it is at the same time mani¬ 
fest, that if the mouth were completely shut, these teeth 
would project beyond those above them. The grinders un¬ 
dergo an analogous displacement, each of the lower ones 
advancing some distance more forwards, than its fellow in 
the upper jaw. The space between the molares of the two 
jaws is not very great, and, in many cases, the thumb can 
scarcely be got between those situated furthest back. 
Except when the accident has been caused by outward 
violence, and the soft parts are much injured, there are only 
two indications in the treatment of a dislocated jaw; viz., to 
reduce the bone, and to keep it reduced. 
In order to accomplish the first of these purposes, the 
patient is to be placed upon a low seat, and his head is to be 
supported against the breast of an assistant, who is to apply 
both his hands close round the forehead. The surgeon 
being in front of the patient, is to put his thumbs, covered 
with a handkerchief, or a thick pair of gloves, as far as he 
can betwixt the back grinders on both sides of the mouth. 
The fore-fingers are then to be applied to the crowns of the 
last lower grinders, while the body of the bone is grasped on 
each side with the rest of the fingers, which are to extend 
obliquely under its base. While the head is steadily held in 
the above way, the surgeon now presses directly downwards 
with his thumbs, by which means the condyles are separated 
a little way from the anterior part of the transverse process of 
the temporal bone. This movement is to be performed in an 
uniform manner, without either raising or depressing the chin. 
The condyles are then to be inclined backwards and a little 
downwards, by pressure applied to the back molares and the 
coronoid process, and at the same time, the chin is to be in¬ 
clined with the fingers upwards and forwards. 
As soon as the condyles slip into the glenoid cavities, the 
muscles generally act, and suddenly shut the mouth, so that, 
if the surgeon were not quickly to move his thumbs towards 
the cheeks from between the grinding teeth, they might be 
injured. Hence the prudence also of protecting them with a 
napkin, handkerchief, or, what is better, a thick pair of 
gloves. It must be acknowledged, however, that the danger 
here spoken of has been rather exaggerated by writers on 
surgery, as upon the reduction taking place, the muscles do 
not shut the mouth with the force generally represented. 
Of the Head. 
The surgical injuries of the head are such as affect the 
scalp—such as produce concussion—such as produce com¬ 
pression of the brain. 
Injuries of the scalp are not exempt from danger, as the 
integuments of the head have free connection with the parts 
within the skull by means of vessels. Contusions of the 
head sometimes occasion abscesses beneath the aponeurosis 
of the occipito-frontalis muscle. The matter ought to be 
evacuated as soon as its existence is ascertained; and, if 
possible, the opening should be made in a depending situa¬ 
tion. 
No wounds are more liable to be followed by erysipelas 
than those of the head; a circumstance explained by Petit, 
Desault, and Bichat, by the supposition, that injuries of the 
head are particularly apt to disorder the hepatic functions, 
and thus produce a state of the constitution favourable to 
the occurrence of the erysipelas. It is on the same prin¬ 
ciple, that these celebrated men, with their countryman M. 
Larrey, attempt to account for the frequency of the abscesses 
found in the livers of persons who have died after injuries of 
the head; a thing which Richerand refers to the liver itself 
generally having suffered a concussion or mechanical injury 
at the same time as the brain. But, whatever may be the 
cause of these events, the facts remain incontestible, that the 
head is particularly liable to erysipelas from wounds, and 
that disorder of the liver, and even abscesses in this organ 
are common consequences of injuries of the head. When 
erysipelas comes on, the pain in the head grows worse; un¬ 
easiness and oppression about the liver are experienced; the 
skin becomes exceedingly hot, and the pulse hard, small, 
contracted, and frequent. The appearance of the wound at 
the same time becomes less favourable. If the injury be 
recent, its lips are puffed up and dry, without any secretion. 
Should it be already in a state of suppuration, the matter is 
yellowish 
