When central intravenous access is required and internal jugular vein (IJV) puncture is chosen, the right–sided vein is generally preferred because it provides a direct pathway to the superior vena cava and avoids thoracic duct injury The aim of this study is to examine the maximum and minimum diameter of internal jugular vein when subjected to varied head elevation angles. The study was conducted at emergency department and critical care units of Peerless Hospital & B.K. Roy Research Centre, Kolkata. Ultrasound IJV was scanned and their diameter measurements were noted in 64 healthy volunteers. The ultrasound machine that was used LOGIQ P5. Our result showed that the difference of mean both Right and Left at head elevation angle of 0, 15, 30 and 45 degree IJV in mm –minimum and maximum were decreased respectively which were statistically significant. But the difference of mean Collapsibility index of both Right and Left head elevation angle of 0, 15, 30 and 45 were increased respectively which were statistically significant. We found that ≥70% Collapsibility index Right IJV in mm was recorded in 8 patients at 15° head elevation, in 15 patients at 30°, in 50 patients at 45° and Left IJV in mm was showed in 1 patients at 15° head elevation, in 2 patients at 30°, in 49 patients at 45°. We concluded that the point of care Ultrasound of IJV scanning during gradual head elevation together with the collapsibility index calculation could be helpful in guidance for the venous outflow assessment.