Posterior relation of poal vein: (A) 1st pa of duodenum, (B) Hepatic aery, (C) Bile duct, (D) IVC
Answer is D. The poal vein usually measures approximately 8 cm in adults. It originates behind the neck of the pancreas and is classically formed by the confluence of the superior mesenteric and splenic veins. ref - BDC 6e vol2 pg282 , researchgate.net