Measure length, width and trajectory Using slicer

Hi there, I am currently trying to simulate the trajectory of a screw, including measuring the length and width. Does anyone know how to draw a line on a spine CT data set using 3D slicer that can be used to determine the trajectory and length, also calculating the width of the line?. if you know of any extensions too, would be very helpful. please see example below, what is missing below is knowing the width of the line.