The renal infundibulum is a funnel-shaped component within the kidney, forming part of its internal drainage system. It collects urine produced by the kidney’s filtering units, facilitating its transport.
Anatomy and Function
The renal infundibulum is located deep inside the kidney, within the renal sinus. It is a funnel-shaped cavity that directly receives urine from the renal papillae, the tips of the renal pyramids. These papillae extend into cup-like minor calyces, which then merge to form major calyces.
The infundibulum connects these major calyces, which converge to form the renal pelvis. Typically, two to three major calyces join to form the renal pelvis. The renal pelvis then narrows to become the ureter, a tube that transports urine to the bladder.
The primary function of the renal infundibulum is to collect and channel urine. After urine is produced by the nephrons and flows through the collecting ducts, it enters the minor calyces, then the major calyces, and finally the infundibula, which direct it into the renal pelvis. This flow ensures urine is efficiently moved out of the kidney for excretion.
Common Conditions
The renal infundibulum can be affected by various medical conditions, with kidney stones being a common issue. These stones are solid masses of minerals and salts that can form within the kidney. They develop when there’s an imbalance of substances like calcium, oxalate, or uric acid in the urine, leading to crystal aggregation.
Kidney stones can form or become lodged within the infundibulum, potentially obstructing urine flow. While small stones might pass without symptoms, larger stones can cause intense pain, known as renal colic, often radiating to the lower back or groin. This pain is frequently accompanied by symptoms such as blood in the urine, nausea, vomiting, and painful or frequent urination.
Another condition affecting this area is infundibular stenosis, a narrowing of the infundibulum. This constriction can lead to a dilation of the calyces upstream from the narrowing. This narrowing can impede urine drainage from a specific part of the kidney, potentially leading to urine stagnation and an increased risk of infection or further stone formation.
Infundibular stenosis, though rare, can contribute to progressive kidney dysfunction. The impact on kidney health can vary, but in some cases, it may lead to chronic kidney disease or end-stage renal disease. The long-term prognosis often depends on the extent of the kidney mass affected and the duration of the condition.