Measurement of Normal Kidney Length by Sonography and Its Relation to Age, Sex, and Body Habitus

Introduction: Normal kidney length is an important indicator of normal renal function.The length ranges from 9 to 13.5cm.Kidney sizes are roughly related to patient's size.The assessment of renal size is an integral part of evaluation of renal diseases for both diagnostic and prognostic purposes.Normal renal longitudinal length reflects normal renal function, & it can be conveniently measured by ultrasonography. Materials and Methods:The aim of this study is to evaluate the normal range of kidney length by Ultrasonography and its correlation with Age, Sex, Height, & Weight in normal Indian population.The measurement scale was fixed to the wall to measure height.Weight was measured by a weight machine.The ultrasound image was taken in both lateral decubitus position and the renal length was measured as the maximum bipolar dimension in longitudinal plane.Observations: The mean length in all Age groups was 94.4±11.8mm of right kidney and 97.4±12mm of left kidney and correlated statistically significantly (p=0.000).The mean length of right kidney in male was 94.7±13.8mm,whereas in female it was 94±9.8mm(p=0.597) and that of left side was 98.2±14mm in male and 96.6±10mm (p=0.343) in female, which was statistically not significant.Discussion: In the present study, there was sharp increase in measurements of length till the age of 20 years and slight increase upto 30 years and thereafter, it remained stable beyond 30 years upto 50 years.In the present study the kidney length was found to be larger on left side in 63.68%, right side in 34.98% and equal in 1.35%.However the difference of length between Male and Female was not statistically significant in the present study.Conclusion: The length of kidney were smaller than previously reported, is probably a reflection of the relatively small body size of South East Asians than western population.Left kidney was larger than Right kidney.With increase in Height, Weight there was an increasing trend in the length of measurement in both the kidneys which were statistically significant.