Fetal Development - 18 Weeks
|Embryology - 2 Jul 2020 Expand to Translate|
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|A personal message from Dr Mark Hill (May 2020)|
|contributors to the site. The good news is Embryology will remain online and I will continue my association with UNSW Australia. I look forward to updating and including the many exciting new discoveries in Embryology!|
Images on this current page show thymus development histology occurring during the 18 week post-fertilization age or 20 week gestational age (GA) second trimester stage of development.
|Fetal Links: fetal | Week 10 | Week 12 | second trimester | third trimester | fetal neural | Fetal Blood Sampling | fetal growth restriction | birth | birth weight | preterm birth | Developmental Origins of Health and Disease | macrosomia | BGD Practical | Medicine Lecture | Science Lecture | Lecture Movie | Category:Human Fetus | Category:Fetal|
Some Recent Findings
An ultrasound study of the position of the spinal cord conus medullaris at 18-22 weeks (20 to 24 weeks ((GA}}) showed that it ended adjacent to vertebrae L2, L2-3 vertebral space, and L3 (73/78, 93%). The conus medullaris (Latin, "medullary cone") is the tapered, lower end of the spinal cord.
- Links: Spinal Cord Development
- Thymus Histology: Fetal Thymus overview | Fetal Thymus Medulla | Fetal Thymus Cortex | Adult Thymus | unlabeled fetal overview | unlabeled fetal medulla |unlabeled fetal thymic corpuscle |unlabeled fetal cortex | unlabeled adult overview | Category:Thymus | Immune System Development
The developing fetal thymus shown below is from a 20 week gestational age (GA), 18 week post-fertilization age, or second trimester stage of development.
Note, there is no specific event occurring in thymus growth during week 18, this happens to be the period available to show fatal histology.
Note: Week 18 post-fertilization age (used throughout this current website) is Week 20 gestational age (LMP). Searches for clinical Week 20 gestational age will match this post-fertilization age.
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Cite this page: Hill, M.A. (2020, July 2) Embryology Fetal Development - 18 Weeks. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Fetal_Development_-_18_Weeks
- © Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G