Accessory lobar hepatic vein

The standard terminology from the Nomina Anatomica Veterinaria only describe the 3 main hepatic veins (left, middle and high hepatic veins). An ad hoc nomenclature was then developed by some authors to clearly identify and describe all other vessels :

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