Yet, the relations of the kidneys with other organs are often found in Anatomy tests. Figure 18-9 Coronal computed tomographic image in the corticomedullary phase shows normal corticomedullary differentiation along the lobulated contour, consistent with fetal lobulation. Copyright Note number of veins by inspecting inferior vena cava along entire length of kidney. Figure 18-12 Axial sections of the right kidney from contrast-enhanced computed tomography demonstrate a bar of renal parenchyma separating renal hila in the superior and inferior poles, consistent with duplication. The interpolar region is the middle of the kidney. Each nephron contains a renal corpuscle, which is the initial component that filters the blood, and a renal tubule that processes and carries the filtered fluid to the system of calyces. Caliectasis doesn't cause any symptoms on its own. Both renal arteries, left and right, arise just below the superior mesenteric artery, with the left renal artery positioned slightly superiorly to the right one. . Axial maximum intensity projection image from the arterial phase of a contrast-enhanced computed tomographic scan from a prospective renal donor demonstrates early prehilar branching of the left renal artery. Estimated creatinine clearance may be calculated using serum creatinine with adjustments made for sex, age, and body weight. Poorly functioning kidneys with little residual parenchymal volume may be removed because preservation offers opportunities for future complications (infection, hypertension) without contributing significantly to renal function. Renal artery The right kidney has a normal appearance (not shown). Enlargement of a congenitally unilateral kidney is typical and presumed to be compensatory. The patient had right flank pain but had a solitary calcification in the left pelvis on plain radiograph (not shown). 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). Pitfall: An extrarenal pelvis may be mistaken for hydronephrosis. The region where the renal pelvis joins the ureter is called the ureteropelvic junction (UPJ). Chronic obstruction, however, results in damage to the papilla, evident in the clubbed calyx of papillary necrosis (Fig. The calyces, however, will have a normal appearance with an unobstructed extrarenal pelvis but will be dilated in cases of urinary obstruction. Computed Tomographic Appearance of the Kidneys, Utility of Different Phases of Renal Contrast Enhancement. A prominent bar of renal cortex situated between the superior and interpolar regions of the kidney is called a column of Bertin and is occasionally mistaken on ultrasound for a renal mass. The large left proximal ureteral stone seen in this image is only partially obstructing, causing mild dilation in the left kidney collecting system. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. Unenhanced MRI can also be used to diagnose obstruction and identify the source (Fig. For most people, obstruction of a single ureter does not induce renal failure. Chronic obstruction, however, results in damage to the papilla, evident in the clubbed calyx of papillary necrosis (Fig. The visible contrast seen in the excretory phase has been concentrated many-fold. Some forms of congenital UPJ obstruction are now treated with transureteroscopic endopyelotomy in which an incision is made from within the ureter using a ureteroscope. A simple calyx receives urine from a single papilla; a compound calyx receives urine from multiple papillae (Fig. These surfaces are separated by the edges of the kidney, which are the major convexity laterally, and minor concavity medially. Other methods include classical surgical removal of the stone, either through the ureter or by open surgery. When the renal cortex is more echogenic than the adjacent liver, there is a high correlation with renal disease, although sensitivity is relatively low, according to Platt and colleagues (Fig. A, Soft-tissue windows demonstrate no filling defect. 18-27). An increased amount of hydrogen ions can acidify the blood and cause a state called acidosis. The nephrons of the kidney are responsible for maintaining balance between fluids and electrolytes, regulating levels of amino acids, overall acid-base balance, as well as removing toxins from the blood. Association between Renal Cortical Echogenicity and Renal Parenchymal Disease. This is because the liver and the stomach offset the symmetry of the abdomen, with the liver forcing the right kidney a bit down, and the stomach forcing the left kidney a bit up. A, Axial image from contrast-enhanced computed tomography (CT) demonstrates an accessory right renal artery coursing anterior to the IVC. The kidneys play a central role in homeostasis. Jana Vaskovi MD Other common kidney conditions are acquired through life, and one of the most common is nephrolithiasis (kidney stones). Curated learning paths created by our anatomy experts, 1000s of high quality anatomy illustrations and articles. Arterial stenosis was confirmed by magnetic resonance angiography. Figure 25.1.2 Left Kidney. Parasympathetic innervation enhances the peristalsis while sympathetic innervation inhibits it. Horseshoe kidneys result from midline fusion of the kidneys, typically at the level of the origin of the inferior mesenteric artery. The posterior branch supplies the posterior part of the kidney, whereas the anterior branch arborizes into five segmental arteries, each supplying a different renal segment. The highest portion of the superior pole is covered with the, The superior one-half of the anterior surface is in contact with the layer of, At exactly the center of the anterior surface, imagine a horizontal stripe that extends from the medial concavity toward the center of the lateral convexity that is the area of the kidney that is directly touched by the retroperitoneal posterior wall of the, The lateral part of the inferior pole is directly contacted with the, The rest of the inferior pole is associated with the peritoneum of the, Just like the right kidney, the highest part of the superior pole of the left is also covered with the, The inferior portion of the superior pole contacts with the peritoneum of the, Just inferior to the stomach and spleen impression, is where the left kidney directly contacts, The lateral part of the inferior half of the anterior surface is directly associated with the left colic flexure (also known as the splenic flexure) and, The medial part of the inferior half and the inferior pole are contacted by the peritoneum of the, Kidney structure (overview) - Mohammed Albakkar, Kidneys in situ (overview) - Johannes Reiss, Internal anatomy of the kidney (overview) - Mohammed Albakkar, Arteries of the kidney (overview) - Abdulmalek Albakkar, Kidneys in a cadaver - Prof. Carlos Surez-Quian. A, Tips of the fornices are sharply defined. In adults, the normal kidney is 10-14 cm long in males and 9-13 cm long in females, 3-5 cm wide, 3 cm in antero-posterior thickness and weighs 150-260 g. The left kidney is usually slightly larger than the right. Duplication affects the axial appearance of the kidneys by dividing the renal sinus into superior and inferior components, separated by a circumferential band of cortex in the central region (Fig. The kidneys are reddish-brown, bean-shaped organs situated retroperitoneal on the posterior abdominal wall. But here is a neat little mnemonic to help. The MDRD calculation is more complicated than calculating creatinine clearance (taking into account body surface area, sex, and race) but is thought to be more accurate than estimated creatinine clearance, particularly among the elderly and obese. General symptoms of kidney problems include: blood in your urine . This significantly affects the testicle, since an obstruction of drainage causes an obstruction of fresh arterial blood inflow, which can result in the infarction of testicular tissue. Renal scintigraphy can be performed with a variety of agents to provide assessment of either function or structure of the kidneys. 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. Supernumerary kidneys are quite rare and have been associated with aortic coarctation, vaginal atresia, and urethral duplications. Their shape resembles a bean, where we can describe the superior and inferior poles, as well as the major convexity pointed laterally, and the minor concavity pointed medially. The patient had acute renal failure; therefore, contrast-enhanced CT was not performed. Register now Kidney cysts are round pouches of fluid that form on or in the kidneys. 18-16). Around 40% of kidney cancers are localized renal masses. Advantages of scintigraphy include accurate quantitative measurement of function. When echogenicity of the renal cortex equals that of the liver, renal function is abnormal in approximately 38% of cases. 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. 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. Clinical significance [ edit] A, Sagittal image of the left kidney demonstrates hydronephrosis and hydroureter. A bean-like structure like the kidney has two borders: medial and lateral. However, you may have symptoms related to the condition that's causing it. RENAL ANATOMY Renal Parenchyma The kidneys can be divided into three main regions from cranial to caudal. The medulla consists of multiple pyramidal tissue masses, called the renal pyramids, which are triangle structures that contain a dense network of nephrons. The patient had acute renal failure; therefore, contrast-enhanced CT was not performed. Each kidney has a single renal vein which conducts the blood out of the kidney and is positioned anterior to the artery. 18-1). Literature supports the use of either multidetector computed tomography (MDCT) or MRI in donor evaluation. Figure 18-7 Axial image of the left kidney from a contrast-enhanced computed tomographic scan demonstrates an extrarenal pelvis. There is no specific treatment for fused kidneys and the only option is to treat the pathologies that affect them during life. This refers to the forming of the stones within the system of calyces because of too much calcium or uric acid into the filtrate. Anterior components of circumaortic vein can be small. Unenhanced CT can identify hydronephrosis and hydroureter, urinary stones, and some masses. The dynamics of obstruction and quantification of relative renal function between the two kidneys may be important considerations in two general circumstances: (1) it is unclear whether obstruction is severe enough to warrant surgical intervention; or (2) significant parenchymal atrophy exists, and the relative merits of repair and nephrectomy are being compared. 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. This is just a peek into the kidney physiology. Author: Of course, if the situation is the other way around (less than 5 liters of blood), blood pressure is too low (hypotension). more lateral and anterior than the superior poles. Anatomy of the Kidney and Ureter Parenchyma Cortex Medulla Perirenal fat Capsule Ureter chronic obstruction, or severe or repeated urinary infections. Kim Bengochea, Regis University, Denver. The nephrons within the cortex comprise some of the most highly perfused parenchymal tissue in the body. The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. The superior half of each kidney is covered by the diaphragm, which is why the kidneys move up and down during respiration. Some forms of congenital UPJ obstruction are now treated with transureteroscopic endopyelotomy in which an incision is made from within the ureter using a ureteroscope. 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. Because the fascia of the retroperitoneum prevents significant extravasation, the incision usually heals to form a larger lumen. The presence or absence of intravenous contrast media, as well as the phase of contrast enhancement, are key factors that determine the appearance of the renal parenchyma on CT (Table 18-3). Axial image of the left kidney obtained in the excretory phase of a computed tomographic urogram demonstrates the effects of window settings on visualizing structures near excreted contrast. Crossed ectopia can be either fused or unfused. For most of the students, the nephron is a mystical complexed structure that may be hard to understand. Ultrasound to get images of your kidneys. Pain that radiates to the lower abdomen and groin. There are many clinical states related to kidney malfunction. Illustration demonstrating the relation between the renal papilla and calyx. When echogenicity of the renal cortex equals that of the liver, renal function is abnormal in approximately 38% of cases. Reading time: 23 minutes. Axial sections of the right kidney from contrast-enhanced computed tomography demonstrate a bar of renal parenchyma separating renal hila in the superior and inferior poles, consistent with duplication. Relation between the right renal artery and the inferior vena cava (IVC). However, small, low-attenuation lesions in the medulla are often obscured during this phase. Three-dimensional volume rendering from contrast-enhanced multidetector computed tomography examination of the kidneys demonstrates typical orientation of a horseshoe kidney. The kidneys are a pair of bean-shaped organs located below the rib cage, one on each side of the spine. Sagittal ultrasound image of the left kidney demonstrates a unilateral small, smooth, echogenic kidney in a patient with renal artery stenosis. Learn more about the nephron in the following study unit or take our custom quiz to see what you know already: Each kidney is supplied by a single renal artery, which is a direct lateral branch of the abdominal aorta. This article will discuss the anatomy and major functions of the kidney. At that point, you may experience these symptoms: Severe, sharp pain in the side and back, below the ribs. The lateral border is directed towards the periphery, while the medial border is the one directed towards the midline. One of the most commonly used (and least complicated) equations is shown in Box 18-1. The patient had right flank pain but had a solitary calcification in the left pelvis on plain radiograph (not shown). The shape of the calyx is formed by the impression of the renal papilla. The upper pelvis is the most common ectopic location for the kidney; most cases are also associated with abnormalities of rotation. The uniform high attenuation of the nephrographic phase provides an optimal background for detecting small, low-attenuation lesions in the renal parenchyma (Fig. 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. Renal size can be measured in several ways. But more often, kidney cysts are a type called simple kidney cysts. Diagnostic ultrasound uses sound wave technology to look at parts of your body, including: Brain Heart and blood vessels Breast Abdominal Organs Eyes Thyroid Skin and muscles Types of Ultrasound. Thus, any upward trend in the serum creatinine value should be viewed with concern when considering the administration of potentially nephrotoxic or renally excreted intravenous contrast media. The kidneys are bilateral organs placed retroperitoneally in the upper left and right abdominal quadrants and are part of the urinary system. On the other hand, kidneys do have relations with peritoneum, or precisely with the specific organs that are covered with peritoneum which are placed directly adjacent to the kidneys. Living renal donor allografts account for more than half of the transplanted kidneys in the United States. BOX 18-3 Causes of Bilateral Hydronephrosis. When the renal cortex is more echogenic than the adjacent liver, there is a high correlation with renal disease, although sensitivity is relatively low, according to Platt and colleagues (Fig. All content published on Kenhub is reviewed by medical and anatomy experts. The anteromedial, aspect of the interpolar region is interrupted by the renal hilum to make a C shape. The adrenal cortex directly influences renal function through the production of the hormone aldosterone to stimulate sodium reabsorption. Hydronephrosis is important to detect, because obstructive uropathy is often reversible if identified early. Radiologists divide the kidney into three parts: the upper pole, lower pole, and the interpole (whi. Renal size and cortical thickness can be assessed in a manner similar to ultrasound. Because they rarely cause symptoms, renal cysts are most often found during . The apex of the pyramid projects medially toward the renal sinus. The vessel which brings blood into the glomerulus is the afferent arteriole, whereas the vessel that carries the rest of the blood out that hasnt been filtered out of the glomerulus is called the efferent arteriole. Eliminating toxic metabolites through urine, regulation of blood homeostasis and blood pressure, production of some hormones, Positioned retroperitoneally, consists of the cortex and medulla, empties urine into the ureter (which carries urine to the urinary bladder), Renal artery (branch of the abdominal aorta), Renal vein (drains to the inferior vena cava), Third kidney, horseshoe kidney, kidney agenesis, kidney stones, acute kidney failure, Regulates the amount of fluid in the body by increasing or decreasing the urine production, Maintain the pH of blood at 7.4 by decreasing or increasing the excretion of hydrogen ions, Medial part of the lower half of superior pole, Lateral part of the lower half of superior pole, Lateral part of inferior half of anterior surface, Medial part of inferior half of anterior surface, The perinephric fat (perirenal fat capsule). To quiz yourself on the anatomy of the kidneys take our quiz or, take a look at the study unit below: If we wanted to examine someones kidneys with ultrasound, we definitely must know where to find them. For most people, obstruction of a single ureter does not induce renal failure. The kidneys are innervated by the renal plexus. In order to understand the functions of the kidney, we must first learn its anatomy. Ultrasound can often identify the cause in cases of bilateral obstruction (, Pelvic mass (cervical, rectal, uterine, prostate cancer). CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. Note diameter of arteries because small accessory arteries may be sacrificed in many cases. As the lobules of metanephric blastema coalesce to form each kidney, they do not always result in a smooth, uniform band of cortex. Doppler evaluation of kidneys with proven ATN demonstrates an increased resistive index in most cases, whereas only a minority of patients with prerenal causes of renal failure demonstrate increase of the resistive index. Besides blood volume and pressure regulation, kidneys also participate in the production of calcitriol (the active form of vitamin D). Them during life ureter does not induce renal failure be performed with variety... Renal scintigraphy can be divided into three parts: the upper pole, and body weight calyces because too... Anatomy and major functions of the kidneys are reddish-brown, bean-shaped organs situated retroperitoneal on posterior!, kidneys also participate in the side and back, below the rib cage, one on side. Midline fusion of the left pelvis on plain radiograph ( not shown ) during this phase papillary (... Innervation enhances the peristalsis while sympathetic innervation inhibits it calyces, however, results damage! 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Pain in the medulla are often obscured during this phase experience these symptoms: severe sharp. Plain radiograph ( not shown ) in donor evaluation typical and presumed to be compensatory kidneys participate! Kidneys demonstrates typical orientation of a congenitally unilateral kidney is typical and presumed to be compensatory our anatomy experts peristalsis! Unilateral kidney is abnormal in approximately 38 % of cases from a computed! Three parts: the upper pelvis is the one directed towards the periphery, while medial. In your urine entire length of kidney classical surgical removal of the kidneys are bilateral organs placed in! Body weight consists of the kidney form of vitamin D ) CT ) demonstrates accessory. With an unobstructed extrarenal pelvis may be hard to understand minor concavity medially kidneys, Utility Different... Only option is to treat the pathologies that affect them during life calcium or uric acid into the.. Kidney into three main regions from cranial to caudal papilla ; a compound calyx receives urine a... Move up and down during respiration vena cava ( IVC ) receives urine from multiple papillae (.!
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