Ozguner Gülnur, Sulak Osman
Department of Anatomy, Faculty of Medicine, Süleyman Demirel University, 32260, Isparta, Turkey,
Surg Radiol Anat. 2014 May;36(4):359-67. doi: 10.1007/s00276-013-1177-2. Epub 2013 Jul 30.
The present study's purpose was to examine the size and location of the thyroid gland using anatomic dissection methods on fetal cadavers.
This study was performed on 200 spontaneously aborted human fetuses (100 males and 100 females) aged between 9 and 40 weeks of gestation. Fetuses without any external and internal pathology or anomaly were included in this study. Fetuses were divided into four groups based on gestational ages as follows: first group 9-12 weeks (first trimester), second group 13-25 weeks (second trimester), third group 26-37 weeks (third trimester) and fourth group 38-40 weeks (full term). The fetuses were also grouped into monthly cohorts as follows: 9-12 weeks, 3rd month; 13-16 weeks, 4th month; 17-20 weeks, 5th month; 21-24 weeks, 6th month; 25-28 weeks, 7th month; 29-32 weeks, 8th month; 33-36 weeks, 9th month; and 37-40 weeks, 10th month. The anterior necks of fetuses were dissected and the thyroid glands exposed. Vertebral and laryngeal levels and the dimensions (width, length, thickness and weight) of the fetal thyroid glands were determined by anatomical dissection methods. The dimensions and ratios of the fetal thyroid gland (weight/fetal body weight) were evaluated.
The mean values and standard deviations of all parameters by gestational weeks, months, and trimesters were calculated. It was found that all parameters increased with gestational age. No significant differences were observed between genders in all parameters (P > 0.05). There were no significant differences between the right and the left sides for parameters of the thyroid glands. The levels of the superior poles of the thyroid lobes were located at the cervical (C) C1-C3 vertebral bodies. The levels of the inferior poles of the thyroid lobes were located at C4-C5 vertebral bodies. The levels of the superior poles of thyroid lobes were located between the upper ½ and lower ½ of the thyroid cartilage or cricoid cartilage. The levels of the inferior poles of the thyroid lobes were located between the second and sixth tracheal rings. The distance between the superior poles of the thyroid gland and the hyoid bone increased throughout the fetal period. The dimensions of fetal thyroid glands increased with gestational age. The ratio between thyroid gland weights and fetal body weights was unchanged during the fetal period.
We believe that the results obtained from this study will be useful in monitoring thyroid glands in the intrauterine period as well as recognizing early diagnosis and treatment of thyroid anomalies. It will also contribute to future studies in obstetrics, perinatology, and fetopathology.
本研究旨在通过对胎儿尸体进行解剖方法来检查甲状腺的大小和位置。
本研究对200例妊娠9至40周的自然流产人类胎儿（100例男性和100例女性）进行。本研究纳入了无任何外部和内部病理或异常的胎儿。根据胎龄将胎儿分为四组，如下：第一组9 - 12周（孕早期），第二组13 - 25周（孕中期），第三组26 - 37周（孕晚期），第四组38 - 40周（足月）。胎儿也按月分组如下：9 - 12周，第3个月；13 - 16周，第4个月；17 - 20周，第5个月；21 - 24周，第6个月；25 - 28周，第7个月；29 - 32周，第8个月；33 - 36周，第9个月；37 - 40周，第10个月。解剖胎儿的前颈部并暴露甲状腺。通过解剖方法确定胎儿甲状腺的椎体和喉部水平以及尺寸（宽度、长度、厚度和重量）。评估胎儿甲状腺的尺寸和比例（重量/胎儿体重）。
计算了按孕周、月份和孕期划分的所有参数的平均值和标准差。发现所有参数均随胎龄增加。所有参数在性别之间未观察到显著差异（P>0.05）。甲状腺各参数在右侧和左侧之间无显著差异。甲状腺叶上极的水平位于颈椎（C）C1 - C3椎体。甲状腺叶下极的水平位于C4 - C5椎体。甲状腺叶上极的水平位于甲状软骨或环状软骨的上半部分和下半部分之间。甲状腺叶下极的水平位于气管环的第二至第六个之间。甲状腺上极与舌骨之间的距离在整个胎儿期增加。胎儿甲状腺的尺寸随胎龄增加。胎儿期甲状腺重量与胎儿体重的比例不变。
我们认为本研究获得的结果将有助于监测宫内甲状腺以及识别甲状腺异常的早期诊断和治疗。它也将有助于产科、围产医学和胎儿病理学的未来研究。
