Universlty of Manitoba, ln Partîal Fulfiìlment - MSpace at the ...

1.1 TERATOLOGY
Birth defects have attracted popular curîosity from the earlìest
tlmes, and scientífic attentìon more recently. Thei r study constitutes
the specÌal ity of Teratology, whîch combines many dîscipl¡nes with¡n the
areas of Developmental Bíology and Cl inical l4edicine. Teratology originally
implled the study of rmonstersr, but has now expanded to embrace the
whole fleld of structurâl and functional defects present at birth.
Three degrees of structural abnormal í tíes may be defîned:
a) \,ariations are slight deviations from the range of normal, such as
the delayed appearance of an ossificat¡on centre.
b) Anomalies are minor structural defects which may remain undetected
and do not produce marked functionaì disability, Examples in the vertebral
column are sacral izatîon of a lumbar vertebra or a symptomless spina bifida
occu I ta .
c) Malformations are more extensive defects present at birth. They may
be major, as in anencephaly (which ís uniformly fatal) or more mînor, as in
the congenital fusíon of two vertebral bodies.
1.2 CLtNICAL il'1PoRTANCE q!: BrRTH pEFECTS
ln recent years congenital malformations have become increasingly
important in cl inical prêctice. Appl ication of the prînciples oi publ ic
health and preventive medicîne, followed by the introductlon of antimicroblal
êgents, have produced a steady decl ine in nrortality from acute
infections. Thus a relatlvely hîgher proportion of deaths in înfancy and
childhood are now attributable to congenital nalformations. Horeover,