Bma Illustrated Medical Dictionary

infarction). It can also be used as a
planned treatment, in which case it is
performed under a brief general anaes-
thesia. Breathing may be maintained
artificially during the procedure.
defoliant poisoning The toxic effects of
plant poisons that cause leaves to drop
off. Defoliants are poisonous if swal-
lowed. Widely used defoliants include
sodium chlorate, potassium chlorate,
phenoxy herbicides, and paraquat.
deformityAny malformation or distor-
tion of part of the body. Deformities
may be congenital (present from birth),
or they may be acquired as a result of
injury, disorder, or disuse. Most congen-
ital deformities are relatively rare. Among
the more common are club-foot (talipes)
and cleft lip and palate. Injuries that can
cause deformity include burns, torn mus-
cles, and broken bones. Disorders that
may cause deformity include nerve prob-
lems, some deficiencies, such as rickets,
and Paget’s diseaseof the bone. Disuse of
a part of the body can lead to deformity
through stiffening and contractureof
unused muscles or tendons. Many defor-

mities can be corrected by orthopaedic

techniques, plastic surgery, or exercise.

degenerationPhysical and/or chemical

changes in cells, tissues, or organs that

reduce their efficiency. It is a feature of

aging and may also be due to a disease

process. Other known causes include

injury, reduced blood supply, poisoning

(by alcohol, for example), or a diet defi-

cient in a specific vitamin. (See also

degenerative disorders.)

degenerative disordersA term cover-

ing a range of conditions in which there

is progressive impairment of the struc-

ture and function of part of the body.

The definition excludes conditions due

to inflammation, infection, altered im-

mune responses, chemical or physical

damage, or cancerous change.

The number of specialized cells or

structures in the organ affected is usu-

ally reduced, and cells are replaced by

connective tissueor scar tissue.

Degenerative nervous system disor-

ders include Alzheimer’s disease, motor

neuron disease, Huntington’s disease,

and Parkinson’s disease. Degenerative

DEFOLIANT POISONING DEGENERATIVE DISORDERS

D

Defibrillator delivers

electric shock and

senses heart beat

Saline

drip

Breathing bag to inflate

lungs with oxygen

Paddle

placed

on chest

Heart

trace

Blood-pressure cuff

DEFIBRILLATION

Jelly pad to
protect skin