interpolar region of kidney anatomy
Dialysis. In this case, the right kidney had more favorable anatomy for laparoscopic donor nephrectomy. (Courtesy of Karl T. Rew, MD) Introduction Synonyms Epidemiology However, you may have symptoms related to the condition that's causing it. The kidneys can be divided into three main regions from cranial to caudal. When hydronephrosis is absent, the causative factor for acute renal failure is almost certainly prerenal or renal. The calcium or uric acid will precipitate and form stones. Technetium 99m-mercaptoacetyltriglycin (MAG3) is excreted by the kidneys (mainly through secretion by proximal tubules) and provides evaluation of renal function, particularly in cases of suspected obstruction. The main function of the kidney is to eliminate excess bodily fluid, salts and byproducts of metabolism this makes kidneys key in the regulation of acid-base balance, blood pressure, and many other homeostatic parameters. But here is a neat little mnemonic to help. Learn more about the anatomy of the kidneys and the urinary system with our urinary system quizzes and labeled diagrams. The ureter and calyces were not dilated (not shown), helping to differentiate this anatomic variant from obstruction. Each end of the kidney is commonly called a pole. 18-6). Figure 18-16 Coronal reformation from contrast-enhanced computed tomography performed for renal donation demonstrates a retroaortic left renal vein crossing the aorta well inferior to the level of the renal hila. 18-4). The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. They extend from lumbar vertebra T12-L3. 18-24). Usually, there are two to three major calyces in the kidney (superior, middle, and inferior), which again unite to form the renal pelvis from which the ureter emerges and leaves the kidney through the hilum. While migrating superiorly, the kidneys rotate medially along their long axes and the inferior supplying mesonephric arteries degenerate. The anteromedial aspect of the interpolar region is interrupted by the renal hilum to make a C shape. The renal corpuscle has two components: the glomerular (Bowmans) capsule in which sits the glomerulus. Advantages of scintigraphy include accurate quantitative measurement of function. Publication types Review MeSH terms Humans The main symptom is severe sharp pain that starts suddenly, usually in your belly or one side of your back, and it may go away just as quickly. Unenhanced CT can identify hydronephrosis and hydroureter, urinary stones, and some masses. Calcifications and renal calculi are notoriously poorly demonstrated with MRI. Table 18-1 provides a quick guide itemizing key imaging findings in the potential renal donor. 18-19). Copyright The phases of nephrogram. Some tumors can be slow to grow while some can be aggressive. The patient had acute renal failure; therefore, contrast-enhanced CT was not performed. Table 18-6 lists the most common causes of bilateral smooth renal atrophy. Unenhanced MRI can also be used to diagnose obstruction and identify the source (Fig. This is called the nutcracker phenomenon. Renal cysts become fairly common as people age and usually do not cause symptoms or harm. If, however, a vessel crosses the UPJ at the level of obstruction, a blind incision made from the inside of the ureteral lumen can result in severe hemorrhage. The nephrons within the cortex comprise some of the most highly perfused parenchymal tissue in the body. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. Ultrasound permits real-time optimization of imaging relative to the axis of each kidney. B, Low-attenuation lesion in the late nephrographic/early excretory phase is less suspicious in appearance. In this way, the consistency of blood is preserved and no important substances are lost. Creatinine is a breakdown product of creatine, found within muscle. An increased amount of hydrogen ions can acidify the blood and cause a state called acidosis. Overview. Duplication of the urinary tract is discussed in detail in Chapter 19. This apical projection is called the renal papilla and it opens to the minor calyx. It is important to note, however, that the appearance of hydronephrosis does not necessarily indicate urinary obstruction (see Hydronephrosis and Its Mimics section later in this chapter). 18-25). The right kidney has a normal appearance (not shown). The patient had acute renal failure; therefore, contrast-enhanced CT was not performed. Any excessive amount of fluid will increase the pressure on the arterial wall and cause the blood pressure to rise (hypertension). The information we provide is grounded on academic literature and peer-reviewed research. The medulla consists of multiple pyramidal tissue masses, called the renal pyramids, which are triangle structures that contain a dense network of nephrons. Arterial stenosis was confirmed by magnetic resonance angiography. When the renal arteries enter the kidney through the hilum, they split into anterior and posterior branches. Aggressive tumors form, grow and spread very quickly. A junctional cortical line is a common septum of capsule typically seen on ultrasound as an echogenic line at the site of fusion between the superior pole and middle third of the kidney (Fig. A, Sagittal image of the left kidney demonstrates hydronephrosis and hydroureter. However, this individual is more likely to show a decline in renal function from an additional insult. The most common cause is renal artery stenosis (see Fig. 3D printed model for a 53-year-old female presenting a 21 15 15 mm renal tumor located in the interpolar region of left kidney, treated by left partial nephrectomy. a bifid renal pelvis, ultimately drained by a common ureter. Each pyramid creates urine and terminates into a renal papilla. The region where the renal pelvis joins the ureter is called the, If the renal pelvis is entirely within the confines of the renal sinus, it is considered intrarenal. Figure 18-19 Sagittal ultrasound image of the right kidney demonstrates increased size and echogenicity of the kidney, findings typical of human immunodeficiency virus nephropathy. The bilateral small smooth kidney pattern describes most of what is often diagnosed on sonography as medical renal disease, although the authors prefer the term renal parenchymal disease. Read more. The initiation is caused by the increase in volume that stretches the walls of the calyces. Medullary cystic disease is encountered only rarely, and in addition to the echogenic atrophic cortex, the medullary pyramids are particularly hypoechoic. Renal cysts are sacs of fluid that form in the kidneys. CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. These surfaces are separated by the edges of the kidney, which are the major convexity laterally, and minor concavity medially. The renal pelvis then tapers like a funnel to join the ureter. Alternatively, the anterior to posterior orientation follows the same pattern: renal vein, renal artery and ureter. The ureter and calyces were not dilated (not shown), helping to differentiate this anatomic variant from obstruction. At the Brady Urological Institute, we believe in the adage, "An ounce of prevention is worth a pound of cure," so we place great emphasis on a thorough metabolic evaluation, so that therapies can be appropriately directed towards reducing the risk of recurrent stone disease. However, small, low-attenuation lesions in the medulla are often obscured during this phase. Now lets pay attention to the borders of the kidneys. Kim Bengochea, Regis University, Denver. In most cases, unenhanced CT is performed when the duration and cause of renal failure are unknown because exposure to iodinated contrast media could impair recovery of renal function. Computed Tomographic Appearance of the Kidneys, Utility of Different Phases of Renal Contrast Enhancement. On ultrasound, the renal cortex is usually echogenic in this setting. Calculation of the estimated renal volume is considered by some to be the most accurate assessment of renal size available with ultrasound, although renal length alone is more commonly reported. CT and MR findings of renal artery stenosis parallel classic findings described on intravenous pyelogram, including one atrophic kidney with delayed nephrogram and excretion that can progress to a persistent nephrogram with hyperconcentrated excreted contrast media (Fig. A, Soft-tissue windows demonstrate no filling defect. On axial sections, the polar regions of the kidney typically form a closed circle or donut shape, with the hole formed by renal sinus fat. Note number of veins by inspecting inferior vena cava along entire length of kidney. In most cases, the kidneys are situated with the inferior poles slightly. Of course, if the situation is the other way around (less than 5 liters of blood), blood pressure is too low (hypotension). The visible contrast seen in the excretory phase has been concentrated many-fold. Lets start with the right kidney anterior surface. Further testing/diagnosis is required. They are usually characterized as "simple" cysts, meaning they have a thin wall and contain water-like fluid. Figure 18-2 Annotated axial image of the right kidney from a contrast-enhanced computed tomographic scan demonstrates hilar anatomy of the kidney. Relation between the right renal artery and the inferior vena cava (IVC). Right-sided pain was related to crossed renal ectopia. Note distance from origin to the first arterial division (Fig. The superior poles (extremities) (T12) of both kidneys are more medially pointed towards the spine than the inferior poles (extremities) (L3). Finally, the arcuate arteries branch into the interlobular arteries which branch off even further by giving afferent arterioles to run blood past the glomerulus for blood filtration. Chronic glomerulonephritis usually causes bilateral increased renal echogenicity with smooth atrophy, whereas renal artery stenosis usually causes a similar but unilateral appearance (Fig. Despite different methods of accumulation, each is sequestered by the renal cortex, providing an opportunity to quantify the volume of renal parenchymal tissue in each kidney. 18-7). B, Mild hydronephrosis results in rounding of the fornices with mild shortening of the papillary impression. Illustration demonstrating the anatomy of the renal collecting system. Normally, the kidney is about the size of a mouse and measures approximately 11-12 cm in length, 5-6 cm in width, and 2.5-3 cm in thickness. A bean-like structure like the kidney has two borders: medial and lateral. As the lobules of metanephric blastema coalesce to form each kidney, they do not always result in a smooth, uniform band of cortex. Figure 18-4 Illustration demonstrating the relation between the renal papilla and calyx. Imaging must provide detailed images of the renal parenchyma and a survey of arterial, venous, and ureteral anatomy. Learn how we can help 1.2k views Reviewed Dec 09, 2022 Thank Prominent extrarenal pelves are typically positioned anteriorly (Fig. Crossed ectopia can be either fused or unfused. This kidney measured 14 cm in length. The fused kidneys can have a variety of orientations, including side by side, in-line, or perpendicular. As the lobules of metanephric blastema coalesce to form each kidney, they do not always result in a smooth, uniform band of cortex. A potential benefit of MRI is the lack of exposure to ionizing radiation, although unenhanced CT would still be required to detect stones (the presence of stones increases the donors risk for renal insufficiency later in life and could disqualify them as a donor candidate). Hydronephrosis is absent, the anterior to posterior orientation follows the same pattern: renal vein, artery. 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