Splenomesenteric vein: formally recognising a clinically relevant section of the portal venous drainage system.

BACKGROUND AND AIMS: The objective of this study was to identify and examine a common vein in the portal system that is not consistently named, and when named, to assess whether fundamental concepts were applied in the process of naming. Essentially, the portal venous system drains 3 regions of the gastrointestinal system into 3 major veins (superior mesenteric - SMV, splenic - SV, and inferior mesenteric - IMV) ultimately forming the portal vein (PV). The SMV is formed from midgut veins generally representing the right side of the abdomen. The IMV is formed from hindgut veins generally representing the left side of the lower abdomen and pelvis, classically draining into the SV. The SV is formed from the foregut veins and generally accepts the IMV. The SV then joins the superior mesenteric vein to become the PV.

MATERIALS AND METHODS: Sixty cadavers were dissected to observe the frequency of this morphology. Current anatomy and atlas texts were reviewed to identify the morphology and nomenclature.

RESULTS: Observations from this study identified a vein being formed from the convergence of the SV and IMV the author named "splenomesenteric vein", which joins the superior mesenteric to form the PV.

CONCLUSIONS: These findings suggest re-evaluating the morphology and nomenclature of this structure because of the pathology and clinical relevance of this area.