Arterial supply to the thyroid gland and the relationship between the recurrent laryngeal nerve and the inferior thyroid artery in human fetal cadavers.

The aim of this study was to identify the arterial supply to the thyroid gland and the relationship between the inferior thyroid artery (ITA) and the recurrent laryngeal nerve (RLN) in fetal cadavers using anatomical dissection. The anterior necks of 200 fetuses were dissected. The origins of the superior thyroid artery (STA) and the ITA and location of the ITA in relation to the entrance of the thyroid lobe were examined. The relationship between the ITA and the RLN was determined. The origins of the STA were classified as: external carotid artery, common carotid artery (CCA), and the thyrolingual trunk. The origins of the ITA were the thyrocervical trunk and the CCA. The ITA was absent on the left side in two cases. The relationship of the RLN to the ITA fell into seven different types. Type 1: the RLN lay posterior to the artery; right (42.5%), left (65%). Type 2: the RLN lay anterior to the artery; right (40.5%), left (22.5%). Type 3: the RLN lay parallel to the artery; right (11.5%), left (7%). Type 4: the RLN lay between the two branches of the artery; right (1%), left (3.5%). Type 5: The extralaryngeal branch of the RLN was detected before it crossed the ITA; right (4.5%), left (0%). Type 6: the ITA lay between the two branches of the RLN; right (0%), left (0.5%). Type 7: the branches of the RLN lay among the branches of the ITA; right (0%), left (0.5%). The results from this study would be useful in future thyroid surgeries.

Anatomical development of urinary bladder during the fetal period.

The aim of this study was to determine the development, location, and size of the urinary bladder during the fetal period. The study was performed on 149 human fetuses between 9 and 40 weeks of gestation. The location of the urinary bladder with respect to transverse plane between the highest point of pubic symphysis and the sacral promontory and median sagittal plane was first determined. The dimensions and the angle of the urinary bladder were measured, and bladder shapes were determined. In addition, the edges of the vesical trigone were measured. There was no significant difference between sexes for any of the parameters (P > 0.05). A significant correlation was observed between all parameters and gestational age (P < 0.001). The urinary bladder was located above the transverse plane in most of the cases (83%) and in the median sagittal plane in every case. It was determined that the angle of bladder did not change and the mean value of the angle was 151 degrees during the fetal period. Bladder was categorized into four different shapes (ellipsoid, round, cuboid, and triangular), and the most common shape found during the fetal period was cuboid. The vesical trigone was an isosceles triangle during the fetal period. The new data provided by this study will enable evaluation of the development of the fetal urinary bladder, and should be useful in several fields such as anatomy, fetopathology, medical imaging, obstetrics, and pediatric urology.

Anatomical development of the fetal uterus.

OBJECTIVE: The objective of this study was to gather data on the morphology of the uterus during its development, to provide detailed information regarding the neighboring structures and its variations using anatomical dissections. STUDY DESIGN: Eighty uteri acquired from female fetuses aged 10-40 weeks of gestation were used in this study. Firstly, the relationship between the fetal uterus and the linea terminalis and the position of the uterus within the pelvic cavity was noted. Then the distance between the fundus of the uterus to the promontory and pubic symphysis were measured. Fetal uteri were classified according to their physical appearances. Finally the lengths of the corpus and cervix in three planes and the anteflexion angle were measured. RESULTS: During the fetal period, the fundus of the uterus was above the linea terminalis in 94% and below it in 6% of the cases. The distance between the fundus of the uterus and the promontory significantly correlated with the distance between the fundus of the uterus and the pubic symphysis (p<0.001). This was true for the correlation between the gestational age and the orthogonal lengths of the uterine corpus and cervix (p<0.001). As the gestational age advanced, the anteflexion angle was noted to reduce from 177 degrees to 120 degrees . The shape of the uterus was either cylindrical, pear-shaped, heart-shaped or hourglass-shaped during the fetal period. CONDENSATION: We believe that the data obtained through dissections of the human fetuses in this study will help identifying uterine developmental variations, anomalies and pathologies and will contribute to the studies carried out in obstetrics, perinatology, forensic medicine and fetal pathology departments.

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.

Morphology of umbilical vessels in human fetuses: a quantitative light microscope study.

OBJECTIVE: To investigate the development of the intra-abdominal part of the umbilical vessels in human fetuses by light microscopy. MATERIALS AND METHODS: The location of the umbilicus and umbilical vessels in the abdominal cavity of 90 human fetuses of gestational ages 10-40 weeks was determined. The external vessel diameter, lumen diameter, wall thickness, tunica adventitia thickness, tunica media thickness and the number of vasa vasorum were recorded from cross-sectlons of the intra-abdominal part of the umbilical vessels. 1985). 1985). RESULTS: Umbilical artery agenesis was observed on the left side in two cases and on the right in one case. There was a positive correlation between gestational age and umbilical vessel measurements. There were differences between the vessel and lumen diameters, tunica media thicknesses of the vessels of the second and third trimesters, and the full-term period. There were also predictable differences between the vessel and lumen diameters, tunica media and tunica adventitia thicknesses of the umbilical vein and umbilical arteries. CONCLUSION: Detailed information on quantitative parameters of umbilical vessels at each gestational age may prove helpful in determining pathologies of umbilical vessels and illuminating certain syndromes.

Immunohistochemical localisation of androgen receptor during sex-specific morphogenesis in the fetal mouse.

The distribution of androgen receptors (ARs) in paraffin serial sections of day 17 and day 18 male and female mouse embryos was investigated. In the cranial section of the genital tract AR expression was restricted to Wolffian structures while Müllerian ducts and surrounding mesenchyme were AR negative. In the fusion zone with the urogenital sinus the epithelial components of the vaginal bud were clearly distinguished by differential AR expression, which was faint in the Wolffian ducts, totally missing in the Müllerian ducts, and intense in the sinus ridges with the most intense expression in the morphogenetically active mesenchyme, indicating a new mechanism of negative control of vagina formation via androgens. Expression of ARs outside the genital tract was observed: (1) in loose interstitial mesenchyme extending into the retroperitoneal space up to the coeliac artery, indicating androgen effects during ascent of the kidneys and descent of intraperitoneal organs, (2) in the trigone of the bladder indicating androgen involvement in the development of the vesico-ureteral junction, and (3) in loose mesenchyme between striated muscle fibres and around pelvic skeletal elements, indicating mediation of androgen effects on the musculoskeletal system via loose mesenchyme.

Growing of caecum and vermiform appendix during the fetal period.

OBJECTIVE: The aim of this study is to investigate the growing of the caecum and the vermiform appendix during the fetal period in human fetuses and the relation between growing and shape of the caecum and the localization of the vermiform appendix. METHODS: 40 male and 40 female externally normal-looking fetuses were studied between 10 and 40 weeks of gestation and were subdivided into fetuses of the 1st, 2nd, and 3rd trimesters and full-term fetuses. The parameters of interest included covering of the caecum with peritoneum, shape of the caecum (long tube, symmetric saccule, asymmetric saccule, extremely large right side--atypical), axial length and width of the caecum localization of the vermiform appendix, length of vermiform appendix and length of the meso-appendix. RESULTS: There was a difference in covering of the caecum with peritoneum between males and females; the caecum was predominantly tube shaped during the fetal period, with the asymmetric saccule towards the end of the fetal period; the localization of the vermiform appendix was subcaecal (39%) during the fetal period and postileal (34%) in female fetuses and subcaecal (48%) in male fetuses--the localization of the vermiform appendix changed according to the caecum shape during the fetal period; we found significant differences in the measurements of vermiform appendix, meso-appendix, and caecum among 1st-, 2nd-, and 3rd-trimester fetuses and full-term fetuses. CONCLUSIONS: There was an increase in the measurements for vermiform appendix, meso-appendix, and caecum with increasing gestational age; the localization of the vermiform appendix depended on the shape of the caecum, was different from that of adults and different between sexes, and there was also a significant difference in covering of the caecum with peritoneum between both sexes.

Estimating the testis volume during the fetal period using the stereological method.

The purpose of the present study is to assess the development of seminiferous tubule volume, stromal volume and total testis volume in the human fetal testis during the fetal period using the stereological method. In this study, we examined 90 testes of 45 human fetuses with no congenital anomalies and pathologies. They were aged between 12 and 40 weeks and localized between the scrotum and the abdomen. Total testis volume, seminiferous tubule volume, and stromal volume were estimated using Cavalier Principles. The weight and density of the testes were calculated as well. During the fetal period, the testes were firstly found on the right in the 27th week and on the left in the 32nd week in the scrotum. At the end of the third trimester and full term, the migration of the testes into scrotum was completed (98%). When the second trimester, third trimester and full term fetuses were compared, the differences between testis volumes were significant (p<0.001). The density of the testes between the groups was not significant (p>0.05). Testis parameters during the fetal period were not significantly (p>0.05) different between the right and left testes localization. The correlation between the fetal testis parameters was significant (p<0.001). Towards the end of the fetal period, the rate of seminiferous tubule volume to stromal volume changed in the favor of seminiferous tubule volume. It was observed that interstitial tissue became more regular and had a good organized structure with the progress of gestational age. In the third trimester, the lumen in the seminiferous tubules became more regular and clear and the interstitial tissue had a clear appearance.

Morphology of the metopic suture during the fetal period.

Assessment of the position and size of the metopic suture and anterior fontanelle is important in the routine examination during fetal period and in newborn infants. The aim of this study is to clarify the average size and its developmental changes of the anterior fontanelle and metopic suture by morphometry. Fifty-one cases were examined over a developmental period ranging from fetus of 14 weeks gestation to full term neonate. The width, and length of heads as well as head circumference of all fetuses were measured. The metopic suture and anterior fontanelle sizes were determined. The nearest distances between the parietal bones to the opposite frontal bones, and the distances between the nasion and lower angle of the anterior fontanelle, bregma and upper angle of the anterior fontanelle were measured. The averages of longitudinal and transverse diameters and areas of anterior fontanelle were calculated. Significant correlation was found between all the parameters and gestational ages, and between the sizes of the metopic suture and of skulls. There was no difference between male and female in any of the parameters. In our study, closed metopic suture was not observed. The anterior fontanelle is easy to palpate, and its enlargement might occasionally be helpful in the clinical examination of the newborn infants. The presence of a wide metopic suture may indicate the possibility of additional defects and anomaly in the newborn.

The growth of the upper and lower extremities of Turkish fetuses during the fetal period.

Prenatal analysis of the fetal structures gives us information about fetal growth and gestational age. The aim of this study was to investigate the morphologic structure of the upper and lower extremities of Turkish fetuses during the fetal period, to measure the morphometric values, and to determine the relationship between CRL (crown-rump length) and growth of the foot. In this study, 106 human fetuses (56 males, 50 females) without external anomalies and aged between 10-40 post-menstrual weeks (PMW) were studied. In the upper extremity, the width of shoulder and the length of the arms, forearms and hands were measured. In the lower extremity, the width of the iliac crest, knee condyles, feet, and heels and the length of the thighs, legs and feet were measured. A significant correlation was found between all parameters taken within the fetal period and PMW (p < 0.001). Statistically significant correlations found between foot-growth measurements and fetal parameters indicate that foot length may be a good predictor of age. The measurements of the upper and lower extremities during fetal period are a reliable parameter for use in the assessment of gestational age. These measurements are particularly useful when other parameters do not accurately predict gestational age in some cases such as hydrocephalus, anencephaly, short-limb dysplasia. Our opinion is that the measurements can be useful to assess gestational age in several fields such as anatomy, pathologic anatomy (fetopathology), forensic medicine, medical imaging, obstetrics and pediatrics.

Measurements of anterior fontanelle during the fetal period.

In this study, we aimed to determine the development of the anterior fontanelle during the fetal period by morphometric measurements. One hundred and five (49 males, 56 females) human fetuses were obtained from Isparta Maternity and Pediatric Hospital. The gestational age ranged from 11 to 40 weeks. In all cases, head circumference, head length and biparietal diameter were recorded. The anterior fontanelle, transverse and longitudinal diameters were measured, and the mean anterior fontanelle size and the anterior fontanelle area were calculated. A significant positive correlation was found between the gestational age and all parameters. During the fetal period, the anterior fontanelle area gradually increased with head circumference. There was a sharp increase in third trimester in the area anterior fontanelle. In the present study, there was no significant difference between sexes regarding the all parameters measured or calculated. The mean anterior fontanelle size was larger than that recorded in previous studies for both sexes. As presented in our study, the dimensions of the anterior fontanelle for each gestational age will be useful in the understanding of development and anatomical variation. It may also be useful in the diagnosis of cranial maldevelopment.

The growth of the testes during the fetal period.

OBJECTIVE: To determine the size and position of the fetal testes during gestation. MATERIALS AND METHODS: The study comprised 48 testes obtained from 24 human fetuses with no congenital abnormalities, aged 14-40 weeks. The development of the fetuses was evaluated by measuring the crown-rump length. Testicular size was assessed as the height, width, thickness and weight, and the position of testes determined during fetal development. RESULTS: The testes in 11 fetuses (22 testes) aged 14-37 weeks were in the abdominal cavity; no testis had descended to the scrotum in any fetus until 27 weeks of gestation. Both testes had descended to the scrotum only in fetuses aged 33-40 weeks. There was no significant difference between right and left testicular size in 13 fetuses (26 testes) aged 27-40 weeks, but size correlated with gestational age (P<0.001). CONCLUSION: All testes had descended to the scrotum by 33 weeks of gestation, but there was considerable variation in position from 27 weeks.