Head, uncinate process, neck, body and tail
Mnemonic
“Head, uncinate, neck, body, tail”, from right to left:
- Head, in the C of the duodenum, with the uncinate process hooking behind the superior mesenteric vessels
- Neck, in front of the formation of the portal vein
- Body, crossing the aorta at L1
- Tail, reaching the splenic hilum in the splenorenal ligament
It is retroperitoneal except the tail, which is why pancreatic pain radiates to the back and is relieved by sitting forward.
“The head bleeds, the tail is cut.” Head tumours cause painless obstructive jaundice with a palpable gallbladder (Courvoisier), while the tail is the part injured during splenectomy.
The uncinate process behind the superior mesenteric vessels is what makes a Whipple’s procedure technically demanding, and involvement of those vessels is what determines resectability.
Blood supply reflects the embryology: the head from the gastroduodenal (foregut and midgut), the body and tail from the splenic artery.
Expansion
- Head - within the C of the duodenum; the commonest site of pancreatic carcinoma
- Uncinate process - the hook projecting behind the superior mesenteric vessels
- Neck - anterior to the formation of the portal vein
- Body - crosses the aorta and left kidney
- Tail - the only intraperitoneal part, reaching the splenic hilum in the splenorenal ligament
A tumour in the head obstructs the bile duct early and presents with painless obstructive jaundice, so it is often resectable. Tumours of the body and tail grow silently and present late.
The uncinate process wrapping behind the superior mesenteric vessels is what makes pancreatic head resection technically demanding, and involvement of those vessels is a key determinant of resectability.