Surg Radiol Anat (2007) 29:543–550 DOI 10.1007/s00276-007-0240-2 123 ORIGINAL ARTICLE Development of spleen during the fetal period BahadÂr Üngör · Mehmet Ali Malas · Osman Sulak · Soner Albay Received: 6 November 2006 / Accepted: 21 June 2007 / Published online: 1 August 2007  Springer-Verlag 2007 Abstract Objective This study was aimed to determine the location and development of the spleen in the human fetuses. Materials and methods The study was carried on 141 dead human fetuses aged between 9 and 40 weeks with no marked pathology and anomaly in the years 2002–2003. The location of spleen with the neighboring structures, the existence of accessory spleens, notches on the borders, Wssures on the surfaces, major ligaments and the shape of spleen and its hilum were established. The spleen was com- pletely observed intraperitoneally (except at the hilum), in the left hypochondrium throughout the fetal period. The length, width, thickness, weight, volume, and the hilum dimensions of spleen were measured. Results The dimensions, weight, and volume of the spleen were increased with the gestational age, and positive signiWcant correlations were determined (P < 0.001). There was no diVerence between sexes in all parameters (P > 0.05). The length of the spleen has ranged between 3.1 and 35.6 mm, between 9 weeks old and 40-week-old fetuses, respectively. One or more accessory spleens have been found in 14% of cases. Conclusion The measurements and location of the spleen according to the gestational age were determined by the present study. The expression of morphometric parameters of the spleen at diVerent gestational ages can be used in determination of pathologies of the spleen and may also contribute to future studies on this issue. Keywords Spleen · Human fetus · Fetal development Introduction Spleen is the largest lymphoid organ and lymphoid tissue aggregation in the body and is described among the second- ary lymphoid organs [4, 14]. The spleen appears at about the sixth week as a localised thickening of the coelomic epithe- lium of the dorsal mesogastrium near its cranial end [6]. Fetal splenomegaly occurs in cases of congenital transpla- cental infections, hematologic diseases, immunological dis- orders, and lipidoses [12, 18]. On the contrary, a hypoplastic spleen is often found in cases of Di George syndrome and sickle cell disease. Therefore, the measurements of fetal splenic size should be a useful diagnostic tool in the detec- tion of congenital splenic pathologies in utero [12, 18]. Studies concerning the development and the morphome- try of the spleen, some of them were carried out on live fetuses or newborns, have been made by the use of ultraso- nography [1, 18]. We have also come across studies in which the weights and dimensions of spleens from dead fetuses or newborns were measured [8, 10, 11, 13, 20]. In our study, dead fetuses Wxed by 10% formaldehyde have been used. In two studies [9, 16] on adults, it has been reported that there is a diVerence between the dimensions of spleens from alive and dead subjects (as spleens from dead subjects being smaller) at a ratio ranging among 25 and 50%. The probable reasons for this diVerence have been claimed to be related to drainage of blood from the spleen, decrease in portal pressure, contraction of capsular B. Üngör (&) Medical Faculty, Anatomy Department, Gaziosmanpasa University, KÂola Yolu, 60100 Tokat, Turkey e-mail: bungor04@yahoo.com M. A. Malas · O. Sulak · S. Albay Medical Faculty, Anatomy Department, Suleyman Demirel University, Isparta, Turkey