Development of the vermiform appendix during the fetal period.

This study aimed to determine the location and development of the vermiform appendix (VA) in terms of morphometry. It was carried out on 80 human fetuses that exhibited neither external pathology nor anomaly and whose gestational ages were between 10 and 40 weeks. The location of the VA and cecum was established. Total VA diameter, lumen diameter, wall thickness, serosa, muscularis and mucosa thickness were measured on microscope slides. The VA was almost always observed in the subcecal region during the fetal period. The length of the VA and the attachment length of the meso-appendix to the VA increased with the gestational age. Lymphocyte aggregation was first seen at the 17th week of the fetal period. Positive and meaningful correlation was found between gestational age and morphometric parameters of the VA. A significant difference was found between the genders in the thickness of mucosa, which was larger in girls (p<0.05). When the proximal, median and distal parts were compared, the thickness of serosa between the proximal and distal parts was also significantly different (p<0.05). The present study has revealed that the VA matures in the second trimester during the fetal period. Furthermore, the morphologic development of the VA is almost uniform from the proximal to distal part.