Flow dynamics in the liver is altered in different hepatobiliary and cardiac pathologies, causing changes in hepatic vasculatures sizes and flow pattern changes which can be assessed by ultrasound (USG) study. Before one can use these measurements and observations to diagnose pathologies, a clear grasp of normality is crucial. In the field of pediatrics, this is particularly challenging as the normal range of measurements may change with age, weight, height, gender and race of children. Taking hepatic veno-occlusive disease as an example, current literature is conflicting regarding whether sonographic findings show consistent association with the disease. Sonographic findings therefore now have limited role in contributing to the diagnosis. This may be related to the lack of a robust age corrected normal range of measurement for reference. Existing literature shows that the normal portal vein diameter varies with age, weight and height and possibly gender. Literature for normal measurements of hepatic vein and hepatic artery in children is lacking. In this study, the investigators aim to conduct a prospective, cross-section observational study to establish the normal measurements ranges of hepatic vein, hepatic artery and portal vein in healthy children in the investigators' locality. Flow patterns, including qualitative assessment and quantitative measurements of resistive index and flow velocities will also be assessed. These age corrected normal measurements will be very helpful in the diagnosis and follow-up of hepatobiliary and cardiac pathologies associated with alterations in dynamics of hepatic circulation.