<prompt> Poal vein is formedBehind the spleenBehind the tail of pancreasBehind the neck of pancreasBehind the second pa of duodenum  <response>: Poal vein is formed behind the neck of pancreas where the splenic vein and superior mesentric vein terminates and continue as poal vein. Ref: Human anatomy, 7th edition, BD Chaurasia, pg:328 