"is the circumaortic left renal vein or venous collar - due to the persistence of subsupracardial and intersupracardial anastomoses and the dorsal limb of the left renal vein."
"the ventral preaortic limb of the left renal vein is obliterated, and the remaining dorsal limb becomes the RLRV which courses obliquely and inferiorly to join left common iliac vein."
"other (non-classified): can involve either kidney"
"Left renal vein anomalies are generally classified into four types 2:"
"There are several variations in renal venous anatomy. Some of these are specific to the left renal vein."