Size and location of the kidneys during the fetal period

A reappraisal of pediatric abdominal surface anatomy utilizing in vivo cross-sectional imaging

Despite being integral to medical and surgical practice, pediatric anatomy has remained relatively neglected except for a few landmark works. Neonatal and pediatric anatomy differs structurally and functionally from adult anatomy in many ways. The aim of the current study was to reappraise common abdominal surface landmarks of important structures in infants and children. After cases with related pathologies had been excluded, computer tomography scans of 90 children were divided into three age groups and systematically analyzed. The vertebral levels of the unpaired branches of the abdominal aorta (AA) were recorded. The vertebral level and relationship to the midline of the bifurcation of the AA and the formation of the inferior vena cava were measured. The renal long axes, costal relationships, renal artery vertebral levels, and hilar vertebral levels were measured. The splenic long axis and relationship to the mid-axillary line were also measured. The renal length was disproportionately large in the youngest age group and increased less with age (7.12 cm, 7.85 cm, 8.86 cm). The renal artery was consistently found around L1; the left kidney was related to the 11th and 12th ribs posteriorly, the right kidney only to the 12th rib. The AA bifurcated to the right of the midline in 10% of children. The unpaired visceral branches of the aorta were commonly found at T12 (celiac artery), L1 (superior mesenteric artery), and L3 (inferior mesenteric artery). The current study provides age-standardized surface landmarks and measurements for major abdominal vascular structures and solid organs in normal children. The clinical applications of these data are multiple and diverse.

A morphological investigation of sexual and lateral dimorphism in the developing metanephric kidney

Sexual dimorphism is a prominent feature of renal physiology and as a consequence, it differentially affects predisposition to many adult kidney diseases. Furthermore the left and right kidneys differ in terms of their position, size and involvement in congenital malformations of the urogenital tract. We set out to determine whether differences in the program of branching morphogenesis that establishes the basic architecture of the kidney were apparent with respect to either sex or laterality in mouse embryonic kidneys. This was achieved using a combination of optical projection tomography imaging and computational analysis of many spatial metrics describing the branched ureteric tree. We undertook a comprehensive assessment of twelve aspects of ureteric morphology across developmental time and we found no consistent differences between kidneys of different sexes or laterality. These results suggest that dimorphism is established after birth or at a physiological or cellular level that is not reflected in the morphology of the ureteric tree.

A morphometric study of suprarenal gland development in the fetal period

PURPOSE

The present study's purpose was to examine the morphometric development of the suprarenal gland using anatomic dissection methods during the fetal period.

METHODS

This study was performed on 172 human fetuses (76 males and 96 females) and 344 fetal suprarenal glands obtained from ages 9-40 weeks of gestation with no external pathology or anomaly. Fetuses were divided into 4 groups between gestational ages as follows: Group 1, 9-12 weeks (first trimester); Group 2, 13-25 weeks (second trimester); Group 3, 26-37 weeks (third trimester); and Group 4, 38-40 weeks (full term). Also, the fetuses were grouped into monthly cohorts: 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 suprarenal glands were dissected in the abdominal cavity. The dimensions (width, length, and thickness), volumes and weights of the suprarenal glands were evaluated. The ratio of the fetal suprarenal gland weight/fetal body weight, the ratio of the fetal suprarenal gland volume/fetal kidney volume, and the ratio of the fetal suprarenal gland dimensions/fetal kidney dimensions were evaluated.

RESULTS

Mean values and standard deviations of all parameters according to gestational weeks and trimesters were calculated. It is found that all parameters increase with gestational age. There was significant correlation between gestational age and all parameters (p < 0.001). No significant differences were observed between sexes for any of the parameters (p > 0.05). There was no difference between the right and left sides of parameters except the thickness of the suprarenal glands. The left suprarenal glands were thicker than the right. The ratio of suprarenal volumes to kidney volumes was determined, and we observed that the ratio decreased during the fetal period.

CONCLUSIONS

We believe that the results obtained from this study will be beneficial in understanding the development of suprarenal glands and also contribute to future studies in obstetrics, perinatology, and fetopathology.