ORIGINAL ARTICLE M. Ali Malas Æ O. Sulak Æ A. Go¨ kc¸imen Æ A. Sari Development of the vermiform appendix during the fetal period Received: 6 January 2003 / Accepted: 18 September 2003 / Published online: 9 April 2004 Ó Springer-Verlag 2004 Abstract 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 al- ways 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 signif- icant 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 com- pared, 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 uni- form from the proximal to distal part. Keywords Vermiform appendix Æ Fetal period Æ Human fetus Æ Development Introduction The vermiform appendix (VA) is located 2 cm below the ileocecal junction and has a close relationship with cecal development during the fetal period. The VA, which arises from the medial wall of the cecum, may be found in a retrocecal, pelvic, subcecal, pre-ileal, retro-ileal or paracecal position. The VA is attached to the ileum by the meso-appendix [16]. Some studies on human fetuses have reported that variations in the morphologic struc- ture and arterial supply of the VA [8, 9]. Some previous studies have evaluated VA morphol- ogy during the fetal period [7, 8, 10]. Buschard and Kjaeldgaard [4] described the location of the VA during the embryonic period. Fitzgerald et al. [5] described the location of the VA and cecum during the fetal period. It has been stated that there might be differences in the location and development of the VA. However, it was stated in the previous studies on the location of the VA that the variation in VA localization was related to cecal development during the fetal period [4, 5, 12, 13, 18]. Limited microscopic information on the VA during the fetal period was also presented in previous studies [7, 17]. Lymphoid aggregations were seen in the lamina propria of the VA at the 20th week of gestation. Lym- phoid aggregations increased in number and shape to- wards the full-term period [7]. We could not find any microscopic study of the growth of the VA. For this reason, the aim of this study was to investigate micro- scopically the growth of the VA during the fetal period in human fetuses and the relation between growth and This study was presented as an oral presentation at the Meeting of the Anatomical Society of Turkey, 25–30 October 1999, Antalya, Turkey M. Ali Malas (&) Æ O. Sulak Department of Anatomy, Medical Faculty, Su¨leyman Demirel University, Isparta, Turkey M. Ali Malas Tıp Faku¨ltesi, Anatomi Anabilim Dalı, Su¨leyman Demirel U ¨ niversitesi, 32260 Isparta, Turkey E-mail: mamalas@hotmail.com Tel.: +90-246-2326657 Fax: +90-246-2371165 A. Go¨kc¸imen Department of Histology Embryology, Medical Faculty, Su¨leyman Demirel University, Isparta, Turkey A. Sari Department of Pathology, Medical Faculty, Su¨leyman Demirel University, Isparta, Turkey Surg Radiol Anat (2004) 26: 202–207 DOI 10.1007/s00276-003-0208-9