Ortho module 2 part A Flashcards
What is considered a normal birthweight?
Can range from 2000 grams to approximately 4000 grams. Birth weight outside this range is suggestive of abnormality.
Which percentiles of the growth curve are considered possibly abnormal?
Below 3rd percentile and above 97th percentile
What important factors influence growth?
Normal variation
Heredity/genetic traits
Changes in body proportions
Gender
Low birth weight
Chronic disease
Psychological/emotional factors
Nutrition
Ethnic/cultural backgrounds
Urban/rural environments
Socio-economic status / family size
Secular trends
How commonly is height inherited?
There is a modest but not perfect correlation of the size of parents to the size of children. Correlation coefficient is approximately 0.5 or less meaning heredity explains not more than 25% of the variation.
How are changes in body proportions evaluated?
Scammon’s growth curves reflect 4 major systems;
Lymphoid
Neural
General
Genital
What growth curves reflect the change in facial proportions?
Changes in facial proportions with growth reflects an interaction between neural and general body growth curves.
What do scammon’s growth curves tell us about the tonsils?
They are relatively large in children because lymphoid tissue grows rapidly in the early years. They shrink in adults and so they are no longer an issue in adults.
What does growth of sex organs early in life indicate?
Can indicate problems of sex hormone production (eg endocrine secreting tumour)
A very sexually precocious child needs medical attention as a result. As dentists we should make a note of patient looking more mature than their age.
How do people grow typically from infancy to adulthood?
The growth rate declines sharply from infancy to childhood.
The growth rate continues to decline to reach a minimum just before puberty.
During puberty an adolescent growth spurt takes place where rapid growth occurs.
Growing typically stops at around 18 years of age.
Where are facial structures derived from?
In the formation of the face; almost all tissue, including muscle and bone is from the ECTODERM
What is the origin of hemifacial microsomia?
Hemifacial microsomia is an example of a problem arising early in embryologic development from loss of neural crest cells before they migrate into the developing face, so it arises at the stage of origin, migration and interaction of cell populations.
At which stage of development does cleft lip/palate arise?
Cleft lip and palate arise after the cell populations are in place, at the stage in the second month of embryonic life when organ systems are being formed.
The upper lip in an adult is derived from which of the facial processes?
The upper lip is derived from the median nasal and maxillary processes. Although failure of fusion between the median and lateral nasal processes results in a cleft lip, the lateral nasal process forms the outer parts of the nose and contributes little or nothing to the ultimate upper lip.
Crouzon’s syndrome and the other malformations due to early closure of craniofacial sutures arise at which of the stages of craniofacial development?
The characteristic hypertelorism and midface deficiency of Crouzon’s syndrome are due to prenatal fusion of the superior and posterior sutures of the maxilla, along the wall of the orbit. This occurs in fetal life, during the final differentiation of tissues, considerably later than the embryologic origin of clefts and related problems.
At what degree of deviation from the normal height-weight standards is special investigation of a child’s status indicated?
<3 percentile
> 97 percentile
