Posterior relations of head of pancreas are all except –
**Core Concept**
The head of the pancreas is a key anatomical structure located in the abdomen, playing a crucial role in digestion and metabolism. Its posterior relations are essential to understanding the spatial relationships between the pancreas and surrounding structures.
**Why the Correct Answer is Right**
The correct answer is related to the anatomical posterior relations of the head of the pancreas. The head of the pancreas is situated behind the first part of the duodenum and the portal vein, and it is related anteriorly to the inferior vena cava and the aorta. The pancreas is closely associated with the superior mesenteric vessels and the portal vein, forming the uncinate process. The posterior relations include the inferior vena cava, aorta, and the superior mesenteric artery and vein.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the inferior vena cava is indeed a posterior relation of the head of the pancreas, as it lies posterior to the head of the pancreas.
**Option B:** This option is incorrect because the aorta is also a posterior relation of the head of the pancreas.
**Option C:** This option is incorrect because the superior mesenteric artery and vein are closely associated with the head of the pancreas, forming the uncinate process, and are therefore considered posterior relations.
**Clinical Pearl / High-Yield Fact**
The head of the pancreas is a critical structure that requires careful consideration when planning surgical procedures, such as pancreaticoduodenectomy, to avoid injury to surrounding structures.
**Correct Answer:** D