Abstract
Background & Aim: The present study is aimed to document the histological changes of thymus gland during different weeks of gestation in human fetuses. Materials & methods: Fifty-three human fetuses (30 males and 23 females) of different age groups ranging from 9th to 40th gestational week were procured from the Department of Obstetrics and Gynaecology, Sree Balaji Medical College and Hospital, Chennai and from Mahathma Gandhi Medical College, Puducherry. The fetuses were dissected. The thymic tissues thus obtained were immersed in I 0% formalin for one week. After proper fixation, the tissue was subjected to routine processing and then the sections were stained with Haematoxylin and Eosin for microscopic examination. Results : Formation of lobules had started at 9th week and distinct formation of lobules was observed during the 12th week. The differentiation of the cortex and the medulla became well distinguished from the 14th week onwards. Presence of Hassall's Corpuscles was observed from 14th week and was found in all sections from 15th week onwards. Hassall's Corpuscles increased in number, size and maturity with the increase in the gestational age. Conclusion: Familiarity with the embryology, anatomy, and dynamic physiology of the thymus is essential for clinicians to avoid unnecessary imaging or invasive procedures.
Histometric study of the mean epidermal thickness from different regions of skin of human fetuses of 11-40 weeks of gestational age
