THE SALIVARY GLANDS
Surgical Anatomy--Injuries--Salivary fistulae--Salivary
calculi--Infective conditions: _Parotitis_; _Inflammation of
submaxillary gland_; _Angina Ludovici_; _Inflammation of
sublingual gland_; _Tuberculous disease_--Tumours: _Ranula_;
_Mixed tumours of parotid_; _Sarcoma_; _Carcinoma_; _Tumours of
submaxillary and sublingual glands_.
#Surgical Anatomy.#--_The parotid gland_ lies on the side of the face
below and in front of the ear, and extends deeply behind the mandible
reaching almost to the side wall of the pharynx. Its deeper part lies
in close relation with the internal carotid artery, the internal
jugular vein, and the vagus, glosso-pharyngeal, accessory, and
hypoglossal nerves. The external carotid artery passes through the
substance of the parotid, and bifurcates opposite the neck of the
condyle into the temporal and internal maxillary arteries. It is
accompanied by the venous trunk formed by the junction of the temporal
and internal maxillary veins. The facial nerve and its branches
traverse the lower third of the gland from behind forwards. The facial
portion of the gland lies on the surface of the masseter muscle, and
the _parotid duct (Stenson's duct)_ emerges from its anterior border.
After crossing the masseter, the duct pierces the buccinator muscle
and the mucous membrane obliquely, and opens into the mouth opposite
the second upper molar tooth. Its course is indicated by a line
passing from the upper part of the lobule of the ear to a point midway
between the ala of the nose and the margin of the upper lip--that
is, at a higher level than the facial nerve. Several lymph
glands--pre-auricular--lie inside the capsule of the parotid just in
front of the ear.
The _submaxillary gland_ lies under the integument and fascia in the
triangle formed by the lower jaw and the two bellies of the digastric
muscle. Its anterior part is crossed by the facial vessels, and
several lymph glands lie inside its capsule. The _submaxillary duct
(Wharton's duct)_ opens into the mouth by the side of the frenum of
the tongue.
The _sublingual gland_ lies in the floor of the mouth just beneath the
mucous membrane. It has numerous ducts, some of which open directly
into the mouth, others into the submaxillary duct.
#Injuries.#--The _parotid_ is frequently injured by accidental wounds
and in the course of operations. If the blood vessels traversing the
gland are divided, such wounds are liable to bleed freely, and if the
facial and auriculo-temporal nerves are damaged, motor and sensory
paralysis of the parts supplied by them ensues. Wounds of the parotid
heal rapidly and without complications so long as infection is
prevented, but if suppuration takes place they are liable to be
followed by the escape of saliva, which may go on for weeks; in some
cases a salivary fistula is thus established.
_The parotid duct_ may be divided and a salivary fistula result. If
the external wound heals rapidly, a salivary cyst may develop in the
substance of the cheek, forming a swelling, which fills up at meals,
and may be emptied by external pressure, the saliva escaping into the
mouth.
In a wound implicating the whole thickness of the cheek the skin
should be accurately sutured, care being taken that the stitches do
not include the duct, but in order that the saliva may readily reach
the mouth, the mucous membrane should not be stitched.
#Salivary Fistulae.#--A salivary fistula may occur in relation to the
glandular substance of the parotid or in relation to the duct. Fistula
in connection with the glandular substance--_parotid fistula_--seldom
results from a wound, made, for example, in the removal of a tumour or
in an operation on the ramus of the jaw, so long as it is aseptic; but
as a sequel of suppuration in the gland, and particularly of an
abscess developing around a concretion, it is not uncommon. The
fistulous opening is usually small, and may occur at any point over
the gland. The fistula may be dry between meals, or the saliva may
escape in small transparent drops, but the quantity is always greatly
increased when food is taken. A parotid fistula, although it may
continue to discharge for weeks, or even for months, usually closes
spontaneously.
In persistent cases, the edges of the fistula may be pared and brought
together with sutures, or the actual cautery may be applied to induce
cicatricial contraction.
_Fistula of the parotid duct_ is more serious. It is usually due to a
wound, less frequently to abscess or impacted calculus. From the
minute opening, which is most frequently situated over the buccinator
muscle, there is an almost continuous flow of clear limpid saliva,
which is greatly increased in quantity while the patient is eating.
These fistulae show little tendency to close spontaneously. Attempts to
close the opening by the external application of collodion, by
cauterising the edges, or even by paring the edges and introducing
sutures, usually fail. It is necessary to establish an opening into
the mouth, either by opening up the original duct or by making an
internal fistula in place of the external one.
#Salivary Calculi.#--Salivary calculi are most commonly met with _in
the submaxillary gland or its duct_. They consist of phosphate and
carbonate of lime with a small proportion of organic matter, and
result from the chemical action of bacteria on the saliva. In rare
cases a foreign body, such as a piece of straw, a fruit-seed, or a
fish-bone, forms the nucleus of the concretion. They vary in size from
a pea to a walnut, and are hard, of a whitish or grey colour, and
rough on the surface. Those that form in the gland itself are usually
irregular, while those met with in the duct are rounded or
spindle-shaped (Fig. 261).
[Illustration: FIG. 261.--Series of Salivary Calculi.]
A calculus in the duct gives rise to sharp lancinating pain, which is
aggravated when the patient takes food. The duct is seldom completely
obstructed, but the flow of saliva is usually so much impeded that the
gland becomes greatly swollen during meals. The swelling gradually
subsides between meals, or can be made to disappear by external
pressure. The calculus can usually be felt by means of a probe passed
along the duct, or by puncturing the swelling with a needle; or, with
one finger inside the mouth and another under the jaw, a hard lump can
be detected under the mucous membrane of the floor of the mouth. It
may be revealed by the X-rays. When the obstruction is complete, a
retention cyst forms in which suppuration is liable to occur, causing
marked aggravation of the symptoms. In some cases the wall of the duct
and the surrounding tissues become thickened and indurated, forming a
swelling which is liable to be mistaken for a malignant growth. The
treatment consists in making an incision through the mucous membrane
over the calculus and extracting it with a scoop or forceps.
INFECTIVE CONDITIONS.--#Parotitis.#--Inflammation of the parotid gland
may be non-suppurative or suppurative.
Of the _non-suppurative_ varieties the most common is the epidemic
form known as _mumps_. This is an acute infective condition, which
usually attacks young children, and implicates both glands, either
simultaneously or consecutively. It runs a definite course, which
lasts for from one to two weeks, and almost invariably ends in
resolution. The parotid gland is swollen and tender, there is pain on
attempting to open the mouth, difficulty in swallowing, and dribbling
of saliva. The surgical interest of this disease lies in the fact that
it is frequently complicated by pain and swelling of the testis,
oedema of the scrotum, and occasionally by a urethral discharge, and
atrophy of the testis has been observed after such an attack. In
females there is sometimes pain in the ovary, tenderness and swelling
of the mamma, and a vaginal discharge.
[Illustration: FIG. 262.--Acute Suppurative Parotitis.]
The parotid on one or both sides may suddenly become swollen and
tender in patients who are taking large doses of mercury, in gouty
subjects, or in patients suffering from infective conditions of the
genito-urinary organs, such as orchitis, ovaritis, urethritis, or
cystitis. The condition is usually transient and leads to no
complications.
_Recurrent enlargement_ of the parotid and submaxillary glands, as
well as of the lachrymal glands, is occasionally met with in adults,
and was first described by Mikulicz. It may be associated with
salivary lithiasis, xerostomia, or organic narrowing of the ducts, but
in the majority of cases no such cause can be discovered (D. M.
Greig). When the parotid is affected the condition tends to be
bilateral and there is some constitutional disturbance. The
submaxillary form is usually unilateral and the symptoms are entirely
local. The affected gland rapidly becomes swollen, painful and tender
to the touch, and the swelling increases markedly while the patient is
eating. Each attack lasts for a few hours to one or two weeks, and
then subsides spontaneously. The intervals between attacks vary from a
few weeks to a year or more. In the course of a few years there is
considerable deformity, and sometimes deficiency in the glandular
secretion, but the disease is not attended by other inconvenience.
Benefit has followed the administration of arsenic and iodides, and
the use of radium and X-rays.
The treatment of these non-suppurative forms of parotitis consists in
relieving the symptoms.
_Suppurative parotitis_ may be due to direct spread of infection from
the mouth along the parotid duct, or to extension of suppurative
processes from the temporo-mandibular joint, the jaw, or a lymph
gland. It is liable to occur also in the course of any disease in
which there is an infection of the blood with pyogenic bacteria, and
has been met with in diphtheria, typhoid fever, scarlet fever,
measles, and other eruptive fevers.
The _post-operative_ form of parotitis is most frequently met with
after laparotomy for such conditions as suppurative appendicitis,
perforated gastric ulcer, ovarian cyst, and pyosalpinx.
These secondary forms are probably due to infection from the mouth
under conditions in which the secretion of saliva is arrested or its
escape from the gland interfered with.
The early symptoms are apt to be overshadowed by those of the general
disease from which the patient suffers. At first the gland is swollen,
hard, and tender, and the seat of constant, dull, boring pain; later
there is redness, oedema, and fluctuation. The movements of the jaw
are restricted and painful, the patient is unable to open the mouth,
and has difficulty in swallowing. The inflammation reaches its height
on the third or fourth day, and usually ends in suppuration. The pus
is scattered in numerous foci throughout the gland, and sometimes
large sloughs form. The dense capsule of the gland prevents the pus
reaching the surface and causes it to burrow among the tissues of the
neck, giving rise to dyspnoea and dysphagia. It may find its way
downwards towards the mediastinum, inwards towards the pharynx--where
it constitutes one form of retro-pharyngeal abscess--or upwards
towards the base of the skull. Not infrequently it burrows into the
temporo-mandibular joint, or escapes by bursting into the external
auditory meatus. Serious haemorrhage may result from erosion of the
vessels traversing the gland or of the internal jugular vein, or
venous thrombosis may ensue. Persistent paralysis may follow
destruction of the facial nerve; and salivary fistulae may form. Death
may take place from toxaemia even before pus forms.
_Treatment._--During the first two or three days hyperaemia is induced
by means of poultices, hot fomentations, or Klapp's suction bells, and
the mouth is frequently washed out with an antiseptic. As soon as
there is reason to believe that pus has formed an incision is made
behind the angle of the jaw, parallel to the branches of the facial
nerve, the abscess opened by Hilton's method, a finger passed into the
gland, and all septa broken down and drainage secured.
Acute infection of the #submaxillary gland# is met with under the same
conditions as that of the parotid. Both glands are occasionally
attacked at the same time.
The acute phlegmonous peri-adenitis of the submaxillary gland, known
as _angina Ludovici_, is referred to at p. 597.
The _treatment_ consists in making incisions through the deep fascia
in order to relieve the tension, or to let out pus if it has formed.
Acute suppurative inflammation of the #sublingual gland# may occur
under the same conditions as in the parotid, and is associated with
the formation of an exceedingly painful and tender swelling under the
tongue. The tongue is gradually pushed against the roof of the mouth,
so that swallowing is difficult and respiration may be seriously
impeded. There is marked constitutional disturbance. An incision into
the swelling is immediately followed by relief of the symptoms.
#Tuberculous disease# of the salivary glands is rare. It usually
begins in the lymph glands within the capsule of the parotid or
submaxillary, and spreads thence to the salivary gland tissue.
TUMOURS.--#Cystic Tumours--Ranula.#--The term ranula is applied to any
cystic tumour formed in connection with the glands in the floor of the
mouth. Formerly these tumours were believed to be retention cysts due
to blocking of the salivary ducts. They are now known to be the result
of a cystic degeneration of one or other of the secreting glands in
the floor of the mouth. They contain a thick glairy fluid, which
differs from saliva in containing a considerable quantity of mucin and
albumin, while it is free from any amylolytic ferment or
sulpho-cyanide of potassium. Numerous degenerated epithelial cells are
found in the fluid.
The _sublingual ranula_ is the most common variety. It appears as a
painless, smooth, tense, globular swelling of a bluish colour. It
usually lies on one side of the frenum, and over it the mucous
membrane moves freely. As it increases in size it gradually pushes the
tongue towards the roof of the mouth, and so causes interference with
speech, mastication, and swallowing. It is to be differentiated from a
retention cyst of the submaxillary gland by the fact that a probe can
usually be passed down the submaxillary duct alongside of the
swelling, and from sublingual dermoid (p. 539).
The _treatment_ consists in making an incision through the mucous
membrane over the swelling, dissecting away the whole of the cyst wall
if possible, and, if any portion cannot be removed, swabbing it with a
solution of chloride of zinc (40 grains to the ounce), after which the
cavity is stuffed with bismuth gauze and allowed to close by
granulation. It is sometimes found more satisfactory to dissect out
the cyst through an incision below the jaw, and in the event of
recurrence this should be undertaken.
Cystic tumours, similar to the sublingual ranula, form in the other
glands in the floor of the mouth--for example, the incisive gland,
which lies just behind the symphysis menti, as well as in the apical
gland on the under aspect of the tip of the tongue. The latter is
distinguished by the fact that it moves with the tongue. In rare cases
children are born with a cystic swelling in the floor of the
mouth--the so-called _congenital ranula_. It is usually due to an
imperfect development of the duct of the submaxillary or sublingual
gland.
#Solid Tumours--Mixed Tumours of the Parotid.#--The most important of
the solid tumours met with in the salivary glands is the so-called
"mixed tumour of the parotid." This was formerly believed to be an
endothelioma derived from a proliferation of the endothelial cells
lining the lymph spaces and blood vessels of the gland. A more
probable view is that it develops from rests derived from the first
branchial arch an not from the parotid. The matrix of the tumour is
made up of cartilaginous, myxomatous, sarcomatous, or angiomatous
tissue, the proportion of these different elements varying in
individual specimens, and it may include some portions that are
adenomatous. A gelatinous substance forms in the intercellular spaces
of the tumour, and may accumulate in sufficient quantity to give rise
to cysts of various sizes. There is reason to believe that the tumours
of the parotid previously described as adenoma, chondroma, angioma,
myxoma, and many of the cases of sarcoma, were really mixed tumours in
which one or other of these tissues predominated.
The tumour usually develops in the vicinity of the parotid, and
presses on the salivary tissue, thinning it out and causing it to
undergo atrophy.
_Clinical Features._--The mixed tumour is usually first observed
between the ages of twenty and thirty. It is of slow growth and
painless, and forms a rounded, nodular swelling, the consistence of
which varies with its structure. The skin over the swelling is normal
in appearance and is not attached to the tumour (Figs. 263, 264). Only
in rare cases does paralysis result from pressure on the facial nerve.
[Illustration: FIG. 263.--Mixed Tumour of Parotid.]
[Illustration: FIG. 264.--Mixed Tumour of the Parotid of over twenty
years' duration.]
Although usually benign, these tumours may, after lasting for years,
take on malignant characters, growing rapidly, implicating adjacent
lymph glands, and showing a marked tendency to recur after removal.
The _treatment_ consists in shelling out the tumour, care being taken
to avoid injuring the facial nerve or the parotid duct by making the
incision and the subsequent cuts in the dissection run parallel to
them. If the tumour is removed early and completely, recurrence is the
exception.
#Sarcoma and carcinoma# are rare. They are very malignant, grow
rapidly, infiltrate surrounding parts, including the skin, and infect
the adjacent lymph glands. There is severe neuralgic pain, and
paralysis from involvement of the facial nerve is an early symptom.
The _treatment_ consists in excising the whole of the parotid gland
with the tumour, no attempt being made to conserve the facial nerve or
other structures traversing it. Recourse should be had to the use of
radium both before and after operation, otherwise recurrence is all
but inevitable.
The _submaxillary and sublingual glands_ may be the seat of the same
varieties of tumour as the parotid. These glands are particularly
liable to become invaded along with the adjacent lymph glands in
epithelioma of the tongue and floor of the mouth.