Bma Illustrated Medical Dictionary

the body. Viscerallarva migrans (toxo-

cariasis) is caused by a type of worm

that normally parasitizes dogs. Cutane-

ouslarva migrans (creeping eruption) is

caused by a form of hookworm infesta-

tion; the larvae penetrate the skin and

move around, leaving intensely itchy

red lines sometimes accompanied by

blistering. Both types of larva migrans

can be treated with anthelmintic drugs.

laryngeal nerveOne of a pair of

nervesthat carry instructions from the

brainto the larynxand send sensations

from the larynx to the brain.

laryngectomySurgical removal of all

or part of the larynxto treat advanced

cancer (see larynx, cancer of). After the

operation, many patients learn to speak

using their oesophagus. There are also

mechanical devices available that are

designed to help generate speech.

laryngitisInflammation of the larynx.

Laryngitis may be acute, lasting only a

few days, or chronic, persisting for a long

period. Acute laryngitis is usually caused

by a viral infection, such as a cold, but

can also be due to an allergy. Chronic

laryngitis may be caused by overuse of

the voice; violent coughing; irritation

from tobacco smoke, alcohol, or fumes;

or damage during surgery. Hoarsenessis

the most common symptom and may

progress to loss of voice. There may also

be throat pain or discomfort and a dry,

irritating cough. Laryngitis due to a viral

infection is often accompanied by fever

and a general feeling of illness. If sputum

(phlegm) is coughed up, or if hoarse-

ness persists for more than 2 weeks,

medical advice should be sought.

laryngoscopyExamination of the lar-

ynxusing a mirror held against the back

of the palate (indirect laryngoscopy), or

a rigid or flexible viewing tube called a

laryngoscope (direct laryngoscopy).

laryngotracheobronchitisInflamma-

tion of the larynx,trachea, and bronchi,

caused by a viral or a bacterial infec-

tion. The disorder is usually mild, but

can be life-threatening. It is a common

cause of croupin young children.

larynxThe organ in the throat respon-

sible for voice production, commonly

called the voice-box. The larynx lies be-

tween the pharynxand the trachea. It

consists of areas of cartilage, the largest

of which is the thyroid cartilage that

projects to form the Adam’s apple. Below

it are the cricoid cartilage and the 2

pyramid-shaped arytenoid cartilages.

Inside the larynx are 2 fibrous sheets

of tissue, the vocal cords, which vibrate

to producevocal sounds when air from

the lungs passes through them. These

vibrations are modified by the tongue,

mouth, and lips to produce speech.

Attached to the top of the thyroid car-

tilage is the epiglottis, a leaf-shaped flap

of cartilage that drops over the larynx to

prevent food from entering the trachea

when swallowing.

larynx, cancer ofA cancerous tumour

of the larynx. The exact causes of this

cancer are not known, but smoking and

high alcohol consumption may be asso-

ciated factors. Hoarsenessis the main

symptom, particularly when the tumour

originates on the vocal cords. At an

advanced stage, symptoms may include

difficulty in breathing and swallowing,

and coughing up blood.

If laryngoscopyreveals a tumour on

the larynx, a biopsyis carried out. If the

tumour is small, radiotherapyor laser

treatmentmay be used. For unrespon-

sive and large tumours, partial or total

laryngectomymay be considered.

larynx, disorders ofLaryngeal disor-

ders (those affecting the larynx) usually

cause hoarsenessas they interfere with

LARYNGEAL NERVE LARYNX, DISORDERS OF

L

LARYNX

Epiglottis

Tonsil

Nasal

cavity

Pharynx

Vocal cords

Trachea

Larynx