Figure 1
From: Evaluation of the ideal length of the Seldinger needle for internal jugular vein catheter placement
To calculate the minimum required Seldinger needle length to safely reach the middle of the lumen of the internal jugular vein, the ultrasound skin–vein distance and an insertion angel of the needle of 45° were used for the following calculation. Assuming an isosceles triangle the distance from skin to the internal jugular vein (b) at a 90° angle was measured by ultrasound. To calculate the distance from the skin to the internal jugular vein at a 45° angle (c) Pythagoras’ theorem (a2 + b2 = c2) was applied.
