The vocal cord, consisting of elastic fibers, has no lymphatic capillaries.
Sparse lymphatics begin only at the fibromuscular junction with the vocalis
fold.
The supraglottic space on the other hand has a rich lymphatic network. A very
dense and partly multilayered capillary network is to be found in the
ventricular fold and the ventricle.
The supraglottic lymphatic pathway converges on the anterior insertion of the
aryepiglottic fold and leaves in smaller collections of vessels along the
neurovascular bundle of the larynx. Submucous and preepiglottic horizontal
anastomoses are to be found in the midline of the larynx and are responsible for
bilateral and contralateral metastases in carcinoma.
The subglottic capillary network is not as dense as the supraglottic. Bilateral
and contralateral invasion of the lymph nodes is again possible via the pre- and
paratracheal lymph nodes. The additional drainage to the peritracheal and
mediastinal lymph nodes is of clinical importance.
The laryngeal lymph is ultimately collected into the superior and inferior deep
cervical lymph nodes.
The mucosal lining of the larynx is adapted to its special position at the
junction of the respiratory and digestive tracts. Stratified squamous
epithelium, partially keratinized, covers the laryngeal surface of the
epiglottis, the vestibule folds, the vestibule of the larynx, and the vocal
cords. Ciliated columnar epithelium covers the remaining parts of the mucosal
surface.
The mucosa of the glottis and supraglottis is firmly bound down to the
underlying tissue, but not so in the subglottic region. Here, the laxity of the
tissue allows a dangerous degree of oedema, especially in children, where the
diameter of the area is relatively smaller than in the adult. In this situation,
a degree of oedema, which would not cause too much trouble to an adult, could be
fatal in childhood.
Reinke's space is a closed cleft beneath the epithelium of the vocal cord with
no glands or lymphatic capillaries. It is of clinical significance in Reinke's
edema.
Physiology
Functions of the larynx are: 1) to control airflow; 2) to initiate phonation; 3)
to protect the lower airway; 4) to fix the thorax.
Vital and Communicative Functions of the Larynx
Phonation
Respiration
on swallowing
on swallowing
Protection of the lower airway
Closure of the aditus
Closure of the glottis
Reflex respiratory arrest
Cough reflex
Fixation of the thorax aided by glottic closure
Phonation. To comprehend how a sound is produced in the larynx it is necessary
to understand the Bernoulli effect. This principle states that during the steady
flow of a fluid or a gas, the pressure is less where the velocity is greater. In
other words, when air passes from one large space to another (i.e. from lung to
pharynx), through a constriction (the glottis), the velocity will be greatest
and the pressure least at the site of the constriction.
When we wish to phonate, the recurrent laryngeal nerves set the vocal cords into
the adducted position (Fig. 41), but because the vocal processes are slightly
bulkier than the membranous cord a slight gap exists between the membranous
cords. The lungs then expel air and the airstream passes through this clink
between the vocal cords. According to the Bernoulli principle, therefore, there
is a drop of pressure at this site and this causes the mucosa of the vocal cords
to be drawn into the gap thus blocking it. At this time the subglottic pressure
rises causing another stream of air to flow through the cords with another
resultant pressure drop and closure of the gap. At this process is repeated a
vibratory pattern develops at the vocal cords and the resulting sound is what we
appreciate as voice. The change of this sound into speech is accomplished by the
tongue, teeth, lips and palate.
Hoarseness is the result of noise formed by endolaryngeal turbulence of the
airstream and irregularities of the normally periodic vibrations of the vocal
cords. The phoniatrician distinguishes very slight, slight, moderate, and severe
hoarseness. With increasing dysphonia, the harmonic part of the vocal sound
decreases from the upper to the lower frequencies, and this can be measured by
sonography. At the same time the noise component become more marked. (Recording
is possible under controlled conditions using tape equipment.)
During respiration. The vocal cords are in the respiratory position (Fig. 40),
i. e., the glottis is opened and is under reflex control which depends on gas
exchange and acid-base balance.
Protection of the lower respiratory tract. The base of the tongue, the posterior
pharyngeal wall, and the faucial pillars are involved in swallowing. The
swallowing reflex transmitted in the glossopharyngeal nerve ensures cessation of
respiration and contraction of the aryepiglottic folds, the vocal cords, and the
vestibular folds, and tilling of the epiglottis by the thyroepiglottic muscle.
Simultaneously, the suprahyoid musculature contracts drawing the larynx
anteriorly and superiorly by 2 to 3 cm.
The cough reflex is stimulated by particles of food penetrating within the
larynx. It consists of a deep reflex inspiration with the larynx open. The
glottis closes with a rising intrathoracic pressure and then opens suddenly with
an explosive expiratory stream, and the foreign body is coughed out.
The larynx is the receptor field for other vasovagal reflexes. Mechanical
irritation of the internal surface of the larynx can induce arrhythmia,
bradycardia, and cardiac arrest. Satisfactory mucosal anesthesia must be ensured
during endolaryngeal procedures. Particular care is necessary during repeated
attempts at intubation, prolonged laryngoscopy, and laryngotracheal obstruction
by foreign bodies, etc.
The vagal reflex can be blocked by atropine and increased by opiates. Reflex
irritability is increased in smokers.
Thoracic fixation. The respiratory system is closed off by the glottis to
provide mechanical assistance during several bodily functions, notably,
coughing, defecation, micturition, vomiting, and parturition. Furthermore, the
pectoral muscles are supplemented when doing chin-ups, while digging, and
breathing during asthma attacks.
TRACHEOBRONCHIAL TREE
Study of the tracheobronchial system is common to several disciplines. The
trachea is largely localized to the neck and is a continuation of the larynx so
that diseases of one organ often affect the other. The tracheobronchial system
is therefore of interest to the otolaryngologist. Furthermore, endoscopic
diagnosis and treatment (bronchoscopy) was developed by ear, nose, and throat
surgeons and is still practiced by them although other specialists in bronchial
diseases such as chest physicians and thoracic surgeons practice diagnostic
bronchoscopy.
Basic anatomy
The trachea begins at the level of CVI-CVII and ends at the level of TIV-TV.
The trachea is attached to the cricoid cartilage which is the most narrow rigid
element of the airway and moves in response to movements of the floor of the
mouth and the cervical muscles It is 10 to 13 cm long in the adult and its lumen
is held open by 16 to 20 horseshoe-shaped cartilaginous rings. The posterior
part of the tube is formed by the membranous part which lies in contact with the
anterior esophageal wall.
The carina. i.e., the origin of the two main bronchi, lies at the level of the
fourth-fifth thoracic vertebra. It has an angle of 55o open inferiorly. The
right main bronchus lies at an angle of about 17o to the midline and is
therefore almost a direct continuation of the trachea. Since it is in this
alignment and since the lumen is larger than that of the left main bronchus,
foreign bodies are most liable to enter it. The left main bronchus is longer
than the right main bronchus and lies at an angle of about 35o to the midline.
The bronchial tree has an extra- and an intrapulmonary course. The
horseshoe-shaped cartilaginous rings of the bronchial wall gradually become
complete rings, encircling the bronchus fully in the more peripheral parts. The
bronchioles do not possess cartilaginous elements in the wall but only a spiral
muscle. Changes in the lumen are produced by the bronchial musculature and
additionally in the middle and small bronchi by the bronchial veins.
The trachea and bronchi are lined by respiratory mucosa which becomes flatter
toward the periphery and passes into a single layer of cubical epithelium in the
bronchioles.
Vascular supply. The trachea is mainly supplied by the inferior thyroid artery
(thyrocervical trunk of the subclavian artery), but there are also connections
with the superior thyroid artery (E.C.A.). The bronchi and the carina derive
their blood supply directly from the aorta through bronchial arteries. There are
numerous anastomoses with the pulmonary arteries for the lung tissue.
Lymphatic drainage. The trachea mainly drains to the lymphatic network of the
neck but also connects with the thoracic lymph system which is important in the
spread of metastases.
Nerve supply. This is provided by the vagus nerve and the sympathetic trunk.
Basic physiology
The main function of the trachea and bronchi is respiration.
Warming, humidification, and cleaning of the inspired air begin in the nose and
are completed in the lower airway so that under normal anatomic conditions the
intratracheal air temperature is maintained about 35oC. This temperature is
considerably lower during mouth breathing. The relative humidity of the
intratracheal air is 95% in normal breathing but considerably lower during mouth
breathing.
ESOPHAGUS
Anatomy
The esophagus begins at the level of the lower border of the cricoid cartilage,
at the level of the sixth cervical vertebra, and ends at the cardia which lies
at the level of the eleventh thoracic vertebra. The opening of the esophagus in
the adult lies about 15 cm from the upper incisor teeth and the cardia at about
(35 to) 41 cm. The entire length of the esophagus is thus approximately 26 cm.
The wall of the esophagus is capable of expanding and contracting and is
resistant to considerable mechanical stress. The wall has four layers: layer of
connective tissue(superficial), muscular layer, submucosa and mucosa. The
internal lining is of stratified nonkeratinized squamous epithelium. The
external longitudinal musculature and internal circular muscle layer form
separate layers of the wall. There are also muscle fibers running spirally.
The esophageal musculature is striated in the upper third, consists of mixed
smooth muscle fibers and striated fibers in the middle third, and is almost
exclusively smooth muscle in the lower third.
The esophagus has 3 anatomical and 2 physiological constrictions.
The anatomical constrictions are:
1. Cricopharyngeal constriction at its mouth.
2. At the bifurcation of trachea.
3. As it passes through the diaphragm.
The physiological constrictions are:
1. At the crossing with the aorta.
2. At the level of the esophageal hiatus, the cardia.
There are cervical, thoracic and abdominal portion of the esophagus.
The blood supply is segmental as is the lymphatic drainage. Innervation is mixed
somatic from the IX-th and X-th cranial nerves and autonomic from the
sympathetic nervous system.
Physiology
The esophagus possesses its own active mobility and also a passive mobility due
to respiration and to movement of the neighbouring great vessels and the heart.
The act of swallowing may be divided into an oral phase which is under voluntary
control and a pharyngeal and esophageal phase. The latter are under reflex
control depending on stimulation of the posterior pharyngeal wall and can be
recognized by the elevation of the larynx.
This entrance of the esophagus and the cardia are usually closed. The entrance
of the esophagus opens during swallowing, and the cardia opens in response to
the oncoming peristaltic wave.
The sphincteric and transport functions can be investigated by the following:
radiography with contrast medium and manometry (intraluminal measurement of
pressure in the esophagus).
Disorders of peristalsis and tone are possible in the following: (1) mechanical
obstruction and narrowing and (2) paralysis of the muscles or nerves.
In presbyesophagus there is a disorder of coordination of the various phases of
mobility with increased tertiary contractions and atonic phases. This causes
prolonged transit time of the food.
Part 4
DISEASES OF THE EAR
DISEASES OF THE EXTERNAL EAR
Otitis externa
The origin of disorders of the skin involving the external ear may not be
immediately recognized, particularly those involving the meatus, and even
manifest disease of the auricle and adjacent skin areas may arise in the meatus
or middle ear. Otitis externa has been classified as localized or generalized.
When it is confined within the external meatus two clinical forms are
recognized: (1) circumscribed otitis extenra or furuncle and (2) diffuse otitis
externa.
The generalized form affecting the meatus, auricle and adjoining areas of skin
may be primarily otological or primary dermatological. In addition, the
condition may be classified as infective, due to bacterial, fungal or viral
agents, and reactive, from contact with numerous external sensitizing agents or
resulting from constitutional allergies. In many cases the disease is of mixed
origin, a primary infective lesion developing an eczematous reaction and vice
versa.
INCIDENCE. The incidence of otitis externa is highest in tropical country with a
high humidity where the symptoms are often severe and recurrences are frequent.
AETIOLOGY. Many factors can be implicated in the onset of otitis externa.
Scratcing the ears with dirty fingers or with contaminated objects such as a
matchstick or a hair-grip, or the use of dirty instruments may introduce
pathogenic organisms to the meatus. If the skin is traumatized infection may
penetrate the barrier of the stratum corneum. Syringing the ear for the removal
of hard wax or badly fitting and infrequently cleaned hearing-aid earpieces may
also cause minor injury and subsequent infection. In other causes allergy is the
primary factor. The development of skin allergy may be due to a large variety of
antigens, many of which are contained in topical applications such as cosmetics
and antibiotic preparations. Intense itching is an early symptom of
sensitization and scratching often leads to secondary infection. A sensitivity
reaction may result from psychological factors such as prolonged mental stress.
BACTERIOLOGY. The normal external meatus contains Staphylococcus albus alone or
in combination with other non-pathogenic organisms. Less often Staphylococcus
aureus or non-haemolytic streptococci are found. In cases of otitis externa the
bacteriological flora is often mixed, and S. aureus and Gram-negative organisms
such as Pseudomonas pyocyanea and Proteus vulgaris are present. Escherichia coli
occurs also in mixed infections. The proportions of these organisms vary with
the geographical area, Ps. pyocyanea being commonest in tropical and subtropical
regions.
Furunculosis
Boils (furuncles) are due to a staphylococcal infection of hair follicles or
sebaceous glands which are present in the skin of the outer cartilaginous part
of the external meatus. They may develop in the superficial layers of the skin
or may be more deeply seated. A boil may occur as a single lesion or as multiple
lesions confined to the ear or associated with boils else where in the body.
They commonly recur, particularly in debilitated individuals and in diabetics.
CLINICAL FEATURES. Furuncles produce severe pain in the ear and tenderness in
the region of the meatus at an early stage. Swelling of the meatal walls may
occlude the meatus thus causing deafness. Fever can take place. The superficial
infection may be seen as a small, red, circumscribed and very tender swelling on
the skin of the meatus. Deep infection is more diffuse and the skin initially
shows no significant change although the area may be tender on gentle pressure.
When a boil is situated on the anterior or inferior meatal wall chewing
movements of the jaw cause increased pain and swelling of the lower eyelid may
be present. If the boil is on the posterior wall the swelling may cause
protrusion of the auricles and obliteration of the postauricular sulcus by
oedema. Infection may spread to lymph glands either anterior to the auricle or
below the tip of the mastoid process. Swelling of the meatus associated with
discharge from the ear may cause difficulty in deciding whether infection is
limited to the outer ear or originates within the middle ear.
DIAGNOSIS. In distinguishing between furunculosis of the external meatus with
oedema and acute otitis media with mastoiditis, several observations should be
noted. (1) A history of recent head cold or influenza is suggestive of
middle-ear infection where as staphylococcal infection in some other area of the
body may point to furunculosis. (2) Careful and gentle otoscopic examination may
reveal a boil and when a normal drumhead can be seen the diagnosis is not in
doubt. (3) Hearing in the affected ear is better in furunculosis than in
mastoiditis. Insertion of an infant-size aural speculum into the meatus, when
possible without causing undue pain, will improve the hearing if no middle-ear
infection is present. (4) Pain in furunculosis is of a continuous, dull
throbbing character and may last for several days until the boil bursts, or is
incised, when there is a scanty yellow discharge. In acute otitis media a sharp
piercing pain varying in duration and intensity occurs and is relieved by the
appearance of discharge which may be copious. The presence of mucus in the
discharge suggests an otitis media. (5) Movement of the auricle and pressure on
the tragus increase pain in furunculosis but not in otitis media. (6) In
furunculosis maximum tenderness is present over the tragus, below and medial to
the lobe of the ear and along the anterior border of the mastoid process.
Tenderness in mastoiditis is more often elicited along the posterior border of
the mastoid and over the mastoid antrum. (7) Obliteration of the postauricular
sulcus with forward displacement of the auricle suggests a furuncle, and this is
confirmed if aspiration of a fluctuant swelling yields pus on piercing skin. If
it is caused by a subperiosteal abscess from mastoid infection pus is not met
with until bone is reached. (8) Mastoid radiographs showing well-developed clear
cells on the affected side will exclude mastoiditis but a retro-auricular oedema
produces some haziness of the cells compared with those of the normal side.
Furunculosis and mastoiditis may occur together and if the latter cannot be
excluded an exploratory operation may be justified. When discharge is present a
swab should be taken to determine the organisms and their sensitivity to
antibiotics.
TREATMENT. Meatal packs consisting of narrow (12 mm) ribbon-gauze wicks soaked
in 10% ichthammol glycerin solution, spirituous solution of the boracic acid,
emulsion of hydrocortisone or unguents, which contains antibiotics and steroids
, gently inserted, have a soothing effect. The wicks are changed daily. Most
furuncles burst spontaneously and the discharge should be removed by dry
mopping, the ichthammol glycerin wicks being continued until the ear is dry.
After-treatment consists in keeping the external meatus clean and applying a
disinfectant such as 1% solution of dioxydinå. The majority of boils are due to
S. aureus infections and a 5-day course of treatment with penicillin gives a
rapid relief of pain, particularly if initially given intramuscularly. Incision
of a boil should be delayed until it is clearly pointing on the skin.
Diffuse Otitis Externa
This condition occurs in acute or chronic stages in which the skin of the
external meatus varies from an acute exfoliative and exudative reaction to a
chronic granular or proliferative state.
The acute stage presents usually as a feeling of heat in the ear, soon changing
to pain which is often severe and is increased by jaw movements. The appearance
of a thin serous discharge is accompanied by easing of the pain. Later the
discharge becomes thicker and purulent and in some infections foul-smelling.
Fever can take place. On examination the meatal skin is inflamed, swollen and
very tender. Deafness of the conductive type is usually present due to
accumulation of discharge and epithelial debris. Enlarged tender peri-auricular
glands are palpable and surrounding oedema may displace the auricle. Wax is
noticeably absent.
The features of the chronic stage are discharge and constant irritation or
itching. The desire to scratch is great and severe at night-time, resulting
often in the meatal skin with narrowing of the lumen may be present, or oedema
and desquamation with superficial ulceration of the skin may occur. The drumhead
is often congested, with a granular surface, and intermittent deafness results
from accumulated debris and narrowing of the external auditory meatus. A swab
should be taken to determine the organisms and their sensitivity to antibiotics.
TREATMENT. The treatment of both stages requires thorough and gentle cleansing
of the external meatus, keeping the ears dry, avoiding trauma by scratching,
attention to personal hygiene and the treatment of associated skin conditions.
In the acute stage local treatment may begin with gentle irrigation of the
meatus with warm isotonic saline followed by dry mopping. An attempt should be
made to see the drumhead and to clean the anteroinferior meatal recess. Provided
that regular toilet of the meatus can be carried out treatment with ear drops
may give satisfactory results. Preparations containing an antiinflammatory
corticosteroid and a broadspectrum antibiotic are effective in many patients,
e.g. drops containing sefamicin and dexamethasone (Sofradex) may be instilled
twice daily. Alternatively, after cleansing, the meatus may be packed with a 12
mm ribbon-gauze wick impregnated with a cream containing corticosteroid and a
broadspectrum antibiotic, this treatment being repeated on alternate days.
Antibiotic drops and ointments should be employed circumspectly because of the
risk of sensitization or secondary fungous infection, and should be related to
results of bacteriological examination.
Local treatment of the chronic stage requires the same meticulous toilet of the
meatus. Swelling of the meatal walls may be relieved by ribbon gauze wicks
soaked in 10% ichthammol glycerin. Irritation, causing reinfection by
scratching, is controlled by packing the meatus with a wick impregnated with an
antibiotic/hydrocortisone cream. As the condition improves the cream may be
lightly applied to the meatal walls by a wool-tipped applicator. Nocturnal
itching may be relieved by sedatives.
Failure to respond to treatment may be caused by an underlying middle-ear
infection, sensitivity of the skin to the local application, usually an
antibiotic, or by secondary fungous infection.
Otomycosis
Mycotic infection of the external auditory meatus is prevalent in tropical and
subtropical climates. The incidence in temperate climates has increased in
proportion to the use of antibiotics which leave a medium sterilized of other
organisms in which the fungus may flourish. The condition should be suspected
when routine treatment fails to relieve a diffuse otitis externa, where there is
continued irritation in the ear and when the mass of debris in the meatus
rapidly re-forms after cleansing. The fungi which are commonly found are
Aspergillus niger and Candida albicans. In aspergillus infections numerous black
specks may be seen in the epithelial debris. Microscopic examination of a smear
from the debris will confirm the diagnosis. Culture and sensitivity tests
demonstrate fungal mycelium.
TREATMENT. Treatment consists in thorough cleansing of the meatus by dry mopping
and the application of nystatin, either in powder or ointment form. Amphotericin
(Fungilin) is also effective in candida infections. Alternatively, drops of 2%
salicylic acid in alcohol, or a ribbon-gauze wick soaked in this solution, may
be applied to the external meatus. Regular attendance for treatment lasting 3 or
4 weeks is necessary for elimination of the infection.
Impacted wax
The accumulated secretion from the ceruminous glands situated in the outer part
of the meatus may form a solid, often hard, mass giving rise to deafness,
autophony and discomfort in the ear. Tinnitus and disturbance of balance may
occur from pressure of the wax on the drumhead, and a cough reflex due to
stimulation of the auricular branch of the vagus has been described. The onset
of deafness is often sudden following washing or bathing, when the entrance of
water to the meatus closes a previously narrow passage for the transmission of
sound by causing the wax to swell and a more profound blockage results.
DIAGNOSIS. Diagnosis is in most cases easily made by otoscopic examination, the
mass or plug having a brown or yellowish colour but sometimes it is black or
greyish when mixed with desquamated epithelium. The drumhead may be partially or
totally obscured from view.
TREATMENT. Wax is removed either by instrumental manipulation (by special hook)
or by syringing. The former method should be reserved for special situations and
perfumed only by a otologist. Syringing is advised for most cases and may be
carried out by trained personnel after the presence of wax has been confirmed.
Sterile saline solution, or boracic lotion (1: 40), or a solution of sodium
bicarbonate warmed to blood heat, should be employed for syringing. The patient
should be seated. The patient's head is inclined slightly downwards and towards
the same side to prevent the fluid from running down the neck. The auricle is
pulled upwards and backwards to straighten out the meatus, and the fluid is
injected along the upper wall of the meatus. Excessive force should not be
exerted to remove wax. If the wax is hard and does not come away easily, it is
better to ask the patient to instil drops of olive oil, almond oil or lukewarm
sodium bicarbonate, for several days to soften the wax, and then return for
syringing. When the wax has been removed, the ear should be inspected to ensure
that none remains. The meatus should be dried with cotton-wool mops after
syringing. This is important because any abrasion of the skin during the
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