Lobar portal vein

The standard terminology from the Nomina Anatomica Veterinaria only describe the 2 branches of the portal vein in his hepatic part. An ad hoc nomenclature was then developed by some authors to clearly identify and describe all other intrahepatic vessels : 

• Lobar portal vein: A vein perfusing  a single hepatic lobe. There may be one, two or more lobar portal veins perfusing a single lobe;
• Main lobar portal vein: The biggest portal vein perfusing a lobe; 
• Minor lobar vein: Any smaller lobar vein with the  same origin as the main lobar vein; 
• Accessory lobar vein: A lobar portal vein having a different origin than the main lobar portal vein; 
• Secondary lobar portal vein: Any further ramification of a  lobar portal vein;

Source: Vascular anatomy of canine hepatic venous system: a basis for liver surgery.  Mari L, Acocella F. Anat Histol Embryol. 2015 Jun;44(3):212-24. doi: 10.1111/ahe.12129. Epub 2014 Aug 5. PMID: 25090952