Head Circumfirence on Childhood | Lecture Note

University:
The University Of Western Ontario
Course:
ANAT 2200B | Systemic Anatomy of the Human Body
Academic year:

2022
Views:

257

Pages:

3
Author:

Kyuwon J.

Girls chart ● HC is used for surrogate marker on brain growth ○ Cerebral cortical expansions ○ White matter growth ○ Synaptogenesis +myelination ■ Indirect effect ○ Since skull expands with the response to the growth of brain ■ HC reliable only in infancy and early childhood ■ Cranial sutures remains patent ● When HC falls under 2SD/crosses percentile it is fair to consider ○ Neuro imaging ■ MRI ○ TORCH infection screening ○ Genetic testing ■ Chromosomal microarray ■ Sequencing ○ Developmental assessment Sex-specific head circumference ● Sex related biological differences ○ Prenatal brain volume ○ Postnatal growth velocity ○ Cortical maturation + synaptogenesis ● General patterns ○ At all ages, male will have larger mean head circumference compared to the female. ○ This pattern is present in ■ Birth ■ Infancy ■ Childhood and adolescence ○ Larger average brain volume in males ● ● ● ● ○ Greater cranial vaults Growth shape is similar in both sexes Difference in absolute scale not in pattern During infancy both sex show ○ Rapid head growth ■ Cortical neurogenesis ■ White matter myelination ■ Skull suture patency ○ Boys have slightly higher growth velocity for first 3-6 mo Early child hood ○ Growth rate declines in both sexes ○ By age 2 ~90% of adult brain size has been achieved ● Sex differences will stabilize, remain parallel High-yield exam ● <-2 SD = microcephaly ○ Matter mor then single measurements ○ Falling percentiles = pathology until proven otherwise ○ Brain growth reflects, this is not for skull growth