Acta Biomedica Scientia

MORPHOLOGICAL VARIATIONS OF THE FETAL THYROID GLAND: A COMPREHENSIVE STUDY ON DIMENSIONS AND DEVELOPMENTAL ANOMALIES

KathirasanV1, Uma Maheswari M

drpebyreddy@gmail.com

Fetal thyroid gland, Anatomical Variations, Isthmus Agenesis, Pyramidal Lobe

The thyroid gland plays a crucial role in endocrine function and metabolic regulation, with its development beginning early in gestation. This study aimed to measure the dimensions of the fetal thyroid gland and investigate its morphological variations across different gestational ages. A total of fifty intact fetuses, ranging from 10 to 36 weeks of gestation, were examined. The fetuses were grouped into three categories: 10-18 weeks, 19-27 weeks, and 28-36 weeks. Thyroid glands were carefully dissected, measured, and preserved for detailed morphometric analysis. The study found that the thyroid gland was consistently related to the 1st through 6th tracheal rings. In 12% of cases, the isthmus, which connects the two lobes of the thyroid gland, was absent. This absence was equally distributed between male and female fetuses. A pyramidal lobe, an additional lobe extending from the thyroid isthmus, was observed in 16% of cases, with 62.5% of these cases occurring in male fetuses. The pyramidal lobe was always associated with the Levator glandulae thyroideae, a fibromuscular structure extending to the hyoid bone. The study also noted that 62.5% of the pyramidal lobes arose from the left side of the isthmus.The findings underscore the importance of recognizing these anatomical variations, which can have significant clinical implications, particularly in surgical and radiological practices. Awareness of such variations is essential for avoiding complications during thyroid surgeries, such as incomplete removal of thyroid tissue in cases involving the pyramidal lobe, which can lead to recurrence of conditions like carcinoma and Graves' disease. This study establishes baseline data on the incidence of thyroid variations in fetuses, contributing valuable information to the field of pediatric surgery and radiology.