What is the correct anteroposterior anatomic relationship at the renal (kidney) hilum?

The Anteroposterior Anatomic Relationship at the Renal Hilum

The correct anteroposterior anatomic relationship at the renal hilum is (a) vein—artery—ureter, with the renal vein being the most anterior structure, followed by the renal artery, and the ureter being the most posterior structure. 1

Anatomical Arrangement of Renal Hilar Structures

• The renal vein is positioned anteriorly in the renal hilum, making it the most superficial of the three main hilar structures 1, 2
• The renal artery is positioned in the middle of the anteroposterior arrangement at the hilum 1
• The ureter (specifically the renal pelvis) is positioned posteriorly, making it the deepest of the three main structures 1, 2

Clinical Significance of This Arrangement

• Understanding the anteroposterior relationship is critical during surgical approaches to the kidney, particularly during transplantation, trauma management, and partial nephrectomy 1
• During ultrasound evaluation of the kidney, the transducer can be moved to locate the renal hilum in the transverse plane, with structures identified based on their anteroposterior relationship 3
• When performing emergency ultrasound of the kidneys, recognizing this anatomical arrangement helps in proper identification of hilar structures 3

Variations in Hilar Anatomy

• While the vein-artery-ureter arrangement is standard, studies have documented six different patterns of structures at the renal hilum, with the classic pattern (vein-artery-ureter) being the most common, occurring in approximately 30.3% of cases 1
• Multiple branching of renal vessels can cause congestion at the hilum, potentially altering the typical arrangement 4
• Some kidneys may have multiple renal veins emerging from the hilum, with most emerging posterior to the renal pelvis in variant cases 2

Surgical Considerations

• During surgical approaches to the kidney, the anterior position of the renal vein makes it the first structure encountered, requiring careful handling to avoid vascular complications 5
• The posterior position of the ureter makes it somewhat protected during anterior surgical approaches but more vulnerable during posterior approaches 5
• When performing selective segmental artery clamping during partial nephrectomy, the middle position of the renal artery in the hilum must be considered for proper access 5

Imaging Considerations

• When performing ultrasound of the kidneys, the transducer can be rotated 90° counter-clockwise from the longitudinal plane to obtain transverse views that better visualize the hilar structures 3
• The anteroposterior diameter of the renal pelvis (the posterior ureter component) is measured at the midpoint of the kidney in the transverse plane, corresponding to the region of the hilar vessels 3
• Understanding this relationship helps in accurate interpretation of hydronephrosis and other pathological conditions affecting the renal collecting system 3, 6