ANAT2341 Lab 6 - Postnatal

From Embryology
Lab 6: Introduction | Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Online Assessment

Introduction

Fetal Head (12 weeks) showing bone and cartilage

The Skull is a unique skeletal structure in several ways: embryonic cellular origin (neural crest), form of ossification (intramembranous and endochondrial) and flexibility (fibrous sutures).

  • The cranial vault (which encloses the brain) bones are formed by intramembranous ossification.
  • While the bones that form the base of the skull are formed by endochondrial ossification.
  • The bones enclosing the brain have large flexible fibrous joints (sutures) which allow:
  1. the head to pass through the birth canal
  2. postnatal brain growth
  • ossification continues postnatally, through puberty until mid 20s.
  • in old age the sutures separating the vault plates are often completely ossified.
  • Flexible fibrous sutures allow growth of the brain to be accomodated by calvarial plate growth.
  • Recent molecular studies have show that noggin (a BMP antagonist) is involved in closure of these sutures.

Postnatal Skull

Skull CT normal sutures.jpg

Skull CT Vertex, later and basal views.[1]

  • rapid brain growth in the early years of life (growth of the neurocranium stopping at about 7 years of age).
  • fontanels usually close by the second year of life
    • posterior fontanel by about 3 months.
    • anterior fontanel by about 20 months.
  • Complete sutural fusion occurs after the third decade of life.

Sutures and Fontanels

  • a - Metopic suture
  • b - coronal sutures
  • c - sagittal suture
  • d - lambdoid suture
  • e - squamosal suture
  • f - anterior fontanel
  • g - posterior fontanel
  • h - sphenoidal fontanel
  • i - mastoid fontanel

Adult Skull

Human skull lateral simplified.png

Adult Skull MRI Links: Skull Development - MRI
Adult Skull Movie 1 icon.jpg
 ‎‎Viscerocranium
Page | Play
Adult Skull Movie 2 icon.jpg
 ‎‎Temporal Bones
Page | Play
Adult Skull Movie 3 icon.jpg
 ‎‎Occipital - Frontal
Page | Play
Adult Skull Movie 4 icon.jpg
 ‎‎Parietal-Zygomatic
Page | Play

Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.

Head Growth

Head growth and corresponding charts differ slightly for girls and boys. Given as head circumference-for-age Birth to: 13 weeks, 2 years, 5 years.

Girls Boys
WHO chart - girls head birth to 5 years.png WHO chart - boys head birth to 5 years.png
Chart PDF | WHO - Girls Chart PDF | WHO - Boys


Links: Growth Charts | Neural Exam Movies | - Standard Head circumference-for-age | WHO Growth Standards
Links: Growth Charts | Neural Exam Movies | - Standard Head circumference-for-age | WHO Growth Standards

Bone Histology

A histological image of a skull bone formation by Intramembranous ossification.

Intramembranous ossification centre.jpg

References

  1. <pubmed>21431034</pubmed>| PMC3056371 | Indian J Radiol Imaging.


Lab 6: Introduction | Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Online Assessment

Glossary Links

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Cite this page: Hill, M.A. (2019, October 22) Embryology ANAT2341 Lab 6 - Postnatal. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/ANAT2341_Lab_6_-_Postnatal

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© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G