Bma Illustrated Medical Dictionary

and, in children, the adenoids, which can

enlarge to block the nasopharynx, forcing

the child to breathe through the mouth.

nasopharynx, cancer ofA cancerous

tumour of the nasopharynxthat usually

spreads to the nasal cavity, nasal sinus-

es, base of the skull, and lymph nodes

in the neck.

Cancer of the nasopharynx is rare in the

West but common in the Far East. Most

common at age 40–50, it affects twice as

many men as women. One cause is

believed to be the Epstein–Barr virus.

Common first signs are recurrent nose-

bleeds, a runny nose, and voice change.

Loss of sense of smell, double vision,

deafness, paralysis of one side of the

face, and severe pain may develop.

Diagnosis is through a biopsy, MRI

scans, and X-rays. Treatment is usually

with radiotherapy, but surgery may also

be performed. If treated early, the out-

look can be good.

natural childbirthSee childbirth, natural.

naturopathyA form of alternative med-

icinebased on the principle that disease

is a result of the accumulation of waste

products and toxins in the body, and

that symptoms reflect the attempts of

the body to rid itself of these sub-

stances. Practitioners of naturopathy

believe that health is maintained by

avoiding anything artificial or unnatural

in the diet or in the environment.

nauseaThe sensation of needing to

vomit. Although nausea may occur with-

out vomiting, the causes are the same.

Most nasal polyps are noncancerous,

but they may need to be removed if

they cause nasal obstruction.

nasal septumThe dividing partition

inside the nose. The nasal septum con-

sists of cartilage at the front and bone

at the rear, both of which are covered by

mucous membrane.

Disorders include a deviated septum

(twisting of the septum to one side),

which may be present from birth or

caused by injury. Surgery may be needed

if breathing is obstructed.

Injury may also cause a haematoma(a

collection of clotted blood) to form bet-

ween the cartilage of the septum and

the wall of one nasal cavity. A haem-

atoma may obstruct breathing and may

become infected, causing an abscessthat

could require surgical drainage.

Rarely, a hole may be eroded in the

nasal septum by tuberculosis, syphilis,

Wegener’s granulomatosis, or as a result

of sniffing cocaine.

nasogastric tubeA narrow plastic tube

that is passed through the nose, down

the oesophagus, and into the stomach.

Nasogastric tubes are commonly used

to suck or drain digestive juices from

the stomach when the intestine is

blocked (as in pyloric stenosis) or is not

working properly (as may occur after an

abdominal operation). A nasogastric

tube is also used to give liquid nourish-

ment to patients who cannot eat (see

feeding, artificial), to obtain specimens

of stomach secretions for examination,

and to wash out the stomach after a

drug overdose or after swallowing a poi-

son (see lavage, gastric).

nasolacrimal ductA channel that drains

tears into the nose. The nasolacrimal

duct forms part of the lacrimal apparatus.

nasopharynxThe passage connecting

the nasal cavity behind the noseto the

top of the throat behind the soft palate.

The nasopharynx is part of the respira-

tory tract and forms the upper section

of the pharynx. During swallowing, the

nasopharynx is sealed off by the soft

palate pressing against the back of the

throat, preventing food from entering. It

contains the lower openings of the

eustachian tubes(passages connecting

the back of the nose to the middle ear)

NASAL SEPTUM NAUSEA

N

NASOPHARYNX

Adenoids

Nasopharynx

Soft palate

Oropharynx

Laryngopharynx

Larynx

Opening of

eustachian

tube