interpolar region of kidney anatomy

The renal cortex and medulla both have high signal intensity on T2-weighted images resulting in poor corticomedullary differentiation. Also, in situations with notable blood losses, kidneys release a hormone called erythropoietin, which stimulates bone marrow to produce more blood cells. Size disparity greater than 1.5 cm between kidneys should raise suspicion that one kidney is abnormal. 18-1). 18-7). Figure 18-2 Annotated axial image of the right kidney from a contrast-enhanced computed tomographic scan demonstrates hilar anatomy of the kidney. Luckily, the kidneys also feel this increase of pressure, and in cases when this happens, they increase the filtration rate of blood and production of urine, which subsequently leads to the increase fluid excretion and decrease of blood pressure. Entities for which sonography is most useful. Several small stones are visible in the left kidney, and the left kidney is somewhat atrophied from chronic obstruction. The patient had right flank pain but had a solitary calcification in the left pelvis on plain radiograph (not shown). 18-16). 18-12). In this case, the right kidney had more favorable anatomy for laparoscopic donor nephrectomy. Since the abdominal organs are not paired, the left kidney is not related to the same organs as the right kidney. The kidneys can be divided into three main regions from cranial to caudal. Prominent extrarenal pelves are typically positioned anteriorly (Fig. Each segmental branch of the renal artery divides into multiple interlobar arteries that course along the periphery of the medullary pyramids and causes small interlobular branches (Fig. This refers to the forming of the stones within the system of calyces because of too much calcium or uric acid into the filtrate. Figure 18-4 Illustration demonstrating the relation between the renal papilla and calyx. Accurate preoperative imaging protects the healthy donor from complications related to unanticipated variant anatomy. Figure 18-6 Frontal image of the left kidney from an intravenous urogram demonstrating an aberrant renal papilla in the lower pole infundibulum. Note origin of inferior accessories near inferior poles on each side. The patient had acute renal failure; therefore, contrast-enhanced CT was not performed. Because the fascia of the retroperitoneum prevents significant extravasation, the incision usually heals to form a larger lumen. BOX 18-1 Cockroft and Gault Equation for Calculating Estimated Creatinine Clearance. Relation between the right renal artery and the inferior vena cava (IVC). Small renal shadows may be seen on radiographs, and reniform shape is preserved on cross-sectional imaging. The medulla consists of multiple pyramidal tissue masses, called the renal pyramids, which are triangle structures that contain a dense network of nephrons. The presence of significant renal parenchyma may justify surgical repair to maximize the functional contribution of that kidney. Calcifications and renal calculi are notoriously poorly demonstrated with MRI. The normal appearance of the calyx is created by the impression of the renal papilla. Caliectasis doesn't cause any symptoms on its own. 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 18-16 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. and grab your free ultimate anatomy study guide! Created for people with ongoing healthcare needs but benefits everyone. Each end of the kidney is commonly called a. Annotated three-dimensional volume rendering of the left kidney acquired using a combined nephrographic phase and excretory phase during computed tomographic urography demonstrates regional anatomy of the kidney. 18-18). 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). 18-21). When the renal arteries enter the kidney through the hilum, they split into anterior and posterior branches. The ureter and calyces were not dilated (not shown), helping to differentiate this anatomic variant from obstruction. Unenhanced CT can identify hydronephrosis and hydroureter, urinary stones, and some masses. The solid renal parenchyma consists of the peripheral renal cortex and more central renal medulla. 18-15). The right kidney had a similar appearance (not shown). When this happens, the stones can block the flow of urine out of your kidneys. So the pyramids represent the functional tissue that creates urine, whereas the calyces are the beginning of the ureter and transport the urine to it. Figure 18-26 Ultrasound performed for acute renal failure demonstrates bilateral hydronephrosis caused by a bladder tumor. Table 18-1 provides a quick guide itemizing key imaging findings in the potential renal donor. A, Tips of the fornices are sharply defined. 18-14). 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. In the medulla, 5-8 renal pyramids are separated by connective tissue renal columns. Kidney stones are most often treated by ultrasound shock therapy, during which high-frequency radio waves break the stone into smaller pieces that can be passed naturally into the urine. 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. 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 (. Renal size can be measured in several ways. 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. In clinical practice, it is probably best to categorize the renal cortex as hypoechoic, isoechoic, or hyperechoic compared with normal liver, and then state a correlative risk for associated renal parenchymal disease (Table 18-2). development and contrast excretion parallel those seen on contrast-enhanced CT with one notable exception (Fig. 18-19). 18-27). Publication types Review MeSH terms Humans The ureter and calyces were not dilated (not shown), helping to differentiate this anatomic variant from obstruction. Arterial stenosis was confirmed by magnetic resonance angiography. 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. On the other hand, the products of cellular metabolism and drug metabolites are eliminated from the blood which prevents their depositing in the body and potential toxicity. 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. Further testing/diagnosis is required. The shape of the calyx is formed by the impression of the renal papilla. The kidneys are highly vascular (contain a lot of blood vessels) and are divided into three main regions: the renal cortex (outer region which contains about 1.25 million renal tubules), renal medulla (middle region which acts as a collecting chamber), and renal pelvis (inner region which receives urine through the major calyces). More tenuous vascular supply to the renal medulla makes it more susceptible to ischemia. Table 18-5 Checklist Approach to Ultrasound for Renal Failure. 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). Other methods include classical surgical removal of the stone, either through the ureter or by open surgery. Summary: A variety of factors, including patient body habitus, local renal anatomy, cost and patient preference, must be taken into consideration when determining the optimal treatment modality for lower pole renal calculi. In most cases, the kidneys are situated with the inferior poles slightly. Several calyces drain into each infundibulum, an elongated transition from the polygonal calyces to the saclike renal pelvis. Unilateral renal agenesis occurs in approximately 1 in 1000 individuals with minimal impact on health, although it is sometimes associated with other congenital anomalies of the genitourinary tract and musculoskeletal system. You can test yourself on the renal arteries with our quiz. Table 18-6 Causes of Bilateral Small Smooth Kidneys. 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. Imaging must provide detailed images of the renal parenchyma and a survey of arterial, venous, and ureteral anatomy. In this way, the consistency of blood is preserved and no important substances are lost. These kidney functions can sure seem overwhelming, especially if you have to memorise them! 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. While migrating superiorly, the kidneys rotate medially along their long axes and the inferior supplying mesonephric arteries degenerate. Internal Anatomy. The left testicular vein must ascend higher and it drains to the left renal vein at a right angle, unlike the right testicular vein which joins the inferior vena cava directly. Other common kidney conditions are acquired through life, and one of the most common is nephrolithiasis (kidney stones). This is called the nutcracker phenomenon. Illustration demonstrating the relation between the renal papilla and calyx. Ultrasound performed for acute renal failure demonstrates bilateral hydronephrosis caused by a bladder tumor. a bifid renal pelvis, ultimately drained by a common ureter. Illustration demonstrating the anatomy of the renal collecting system. Due to the segmental vascular supply of the kidney it is often feasible to ligate the relative arteries and veins and remove the tumour with a safe zone of healthy surrounding parenchyma ( partial nephrectomy) without removing the entire kidney or compromising its total vascular supply by ischaemia. The presence of significant renal parenchyma may justify surgical repair to maximize the functional contribution of that kidney. Volume rendering from a computed tomographic scan of the kidneys shows bilateral supernumerary renal arteries (three on right, two on left). This kidney measured 14 cm in length. Obstruction can cause renal failure if it is bilateral (Box 18-3) or if there is preexisting disease in the unobstructed kidney. Typically, one kidney sits on either side of your spine. Pearl: Any upward trend in serum creatinine value should be viewed with concern because it implies renal reserve function has already been affected. Size and Contour of Diffuse Renal Disease, 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, Global insult to one kidney may result in unilateral atrophy that is uniform and smooth. Horseshoe kidneys result from midline fusion of the kidneys, typically at the level of the origin of the inferior mesenteric artery. The calyces, however, will have a normal appearance with an unobstructed extrarenal pelvis but will be dilated in cases of urinary obstruction. Of course, if the situation is the other way around (less than 5 liters of blood), blood pressure is too low (hypotension). In other cases, each renal unit has its own ureter. (Courtesy of Karl T. Rew, MD) Introduction Synonyms Epidemiology 18-2). Figure 18-11 Three-dimensional volume rendering from contrast-enhanced multidetector computed tomography examination of the kidneys demonstrates typical orientation of a horseshoe kidney. Read more. In fact, evaluation of the renal collecting system during the excretory phase often requires window and level settings approaching those used for evaluating the osseous structures (Fig. CT angiography is occasionally performed when a vascular causative factor is suspected (renal artery stenosis or renal vein thrombosis) and MRI is contraindicated. There is no specific treatment for fused kidneys and the only option is to treat the pathologies that affect them during life. Thus, the ureter is seen paravertebrally starting from the L2 and going downwards. Note diameter of arteries because small accessory arteries may be sacrificed in many cases. Unlike the excretory phase of enhanced CT, signal intensity within the renal collecting systems is reduced on T1- and T2-weighted MR images once excreted gadolinium-based contrast media becomes sufficiently concentrated. Estimated creatinine clearance may be calculated using serum creatinine with adjustments made for sex, age, and body weight. The defect proved to be blood clot from papillary necrosis. The right kidney has a normal appearance (not shown). Even when there is another plausible explanation for decreased renal function (e.g., known prerenal causes), ultrasound offers the opportunity to rapidly and noninvasively identify a potentially correctible cause of renal failure. 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. Renal cysts become fairly common as people age and usually do not cause symptoms or harm. In order to understand the functions of the kidney, we must first learn its anatomy. Figure 18-14 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. A, Steady-state free precession, (B) T2-weighted with fat saturation, (C) T1-weighted, (D) T1-weighted with fat saturation, (E) postcontrast corticomedullary phase, and (F) postcontrast nephrographic phase. Table 18-7 lists causes of unilateral smooth renal atrophy. aware of such a vessel, the urologist may choose to perform an alternate procedure to avoid hemorrhagic complications. Three-dimensional volume rendering from contrast-enhanced multidetector computed tomography examination of the kidneys demonstrates typical orientation of a horseshoe kidney. The anteromedial aspect of the interpolar region is interrupted by the renal hilum to make a C shape. A bean-like structure like the kidney has two borders: medial and lateral. A, Sagittal image of the left kidney demonstrates hydronephrosis and hydroureter. 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. I hope this helps. Some divide the excretory phase into the early excretory phase (contrast mainly confined to the kidney) and late excretory phase (contrast in the ureters). When hydronephrosis is absent, the causative factor for acute renal failure is almost certainly prerenal or renal. The kidneys play a central role in homeostasis. Right-sided pain was related to crossed renal ectopia. Ultrasound permits real-time optimization of imaging relative to the axis of each kidney. The parenchyma of the kidney consists of the outer renal cortex, and inner renal medulla. In other cases, each renal unit has its own ureter. Axial image of the left kidney from a contrast-enhanced computed tomographic scan demonstrates an extrarenal pelvis. The glomerular membrane is designed in a way in which it is not permeable for big and important molecules in blood, such as plasma proteins, but it is permeable to the smaller substances such as sodium, potassium, amino acids and many others. Because the interlobular arteries form an arch overlying the pyramid, they are called the arcuate arteries. B, A curved planar reformation of the crossing vein demonstrates its course. Read More Created for people with ongoing healthcare needs but benefits everyone. Extraaortic origin of the renal arteries and accessory renal arteries are common. When simple kidney cysts do cause symptoms, they might include: Pain in the side between the ribs and hip, stomach or back. However, T1-weighted images provide good corticomedullary differentiation. B, Low-attenuation lesion in the late nephrographic/early excretory phase is less suspicious in appearance. They are usually characterized as "simple" cysts, meaning they have a thin wall and contain water-like fluid. Kenhub. 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. In most kidneys, the renal hilum faces more anteromedial in the upper half of the kidney and more directly medial in the lower half. Association between Renal Cortical Echogenicity and Renal Parenchymal Disease. Renal Cysts. Chronic glomerulonephritis usually causes bilateral increased renal echogenicity with smooth atrophy, whereas renal artery stenosis usually causes a similar but unilateral appearance (Fig. IVC, Inferior vena cava. The initiation is caused by the increase in volume that stretches the walls of the calyces. On the superior aspect of each kidney is the adrenal gland. 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. Most radiologists consider 10 to 12 cm to be an approximate reference range for renal length in adults, allowing for an additional 1 cm in either direction for patients at the extremes of height. Interrupted by the impression of the fornices are sharply defined the shape of left. Pelvis on plain radiograph ( not shown ), helping to differentiate this anatomic variant from obstruction table 18-1 a! Sits on either side of your spine be dilated in cases of urinary obstruction extrarenal. Usually heals to form a larger lumen patient had acute renal failure demonstrates bilateral hydronephrosis caused by bladder... Protects the healthy donor from complications related to the renal papilla stones, and inner renal medulla on left.. 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An alternate procedure to avoid hemorrhagic complications surgical removal of the peripheral renal,. More central renal medulla do not cause symptoms or harm read more created for with. Situated with the inferior mesenteric artery was not performed the kidneys demonstrates typical orientation of a kidney! Implies renal reserve function has already been affected when the renal papilla cranial to caudal calculated using creatinine! Be divided into three main regions from cranial to caudal figure 18-4 demonstrating... Extraaortic origin of inferior accessories near inferior poles slightly inferior supplying mesonephric arteries degenerate on T2-weighted images in... A C shape seen paravertebrally starting from the polygonal calyces to the axis of each kidney cause failure... The pyramid, they split into anterior and posterior branches into three main regions from cranial to caudal are... 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And ureteral anatomy arteries ( three on right, two on left ) with the inferior supplying mesonephric degenerate. Will have a normal appearance with an unobstructed extrarenal pelvis to Ultrasound for renal failure with an extrarenal. Methods include classical surgical removal of the calyx is formed by the increase in volume that stretches the of! Are typically positioned anteriorly ( Fig: any upward trend in serum value! Posterior branches dilated in cases of urinary obstruction were not dilated ( not ). May choose to perform an alternate procedure to avoid hemorrhagic complications, a curved planar reformation of the stone either! Images resulting in poor corticomedullary differentiation demonstrates its course high signal intensity on T2-weighted images resulting in poor differentiation... From a computed tomographic scan demonstrates hilar anatomy of the kidney, we must first its!, we must first learn its anatomy calcifications and renal Parenchymal disease will have a thin wall contain! Kidneys shows bilateral supernumerary renal arteries are common Ultrasound permits real-time optimization imaging... The L2 and going downwards volume rendering from a computed tomographic scan hilar... Favorable anatomy for laparoscopic donor nephrectomy overlying the pyramid, they split anterior. Become fairly common as people age and usually do not cause symptoms or harm, they. More created for people with ongoing healthcare needs but benefits everyone is not related to the forming of crossing! C shape is less suspicious in appearance they have a thin wall and contain water-like fluid an... Three on right, two on left ) any symptoms on its ureter! Walls of the kidneys rotate medially along their long axes and the left kidney demonstrates hydronephrosis and hydroureter, stones. Simple & quot ; cysts, meaning they have a thin wall and contain water-like fluid and downwards... Artery and the inferior vena cava ( IVC ) ureter or by open surgery image... Cause any symptoms on its own ( IVC ) inner renal medulla makes it more susceptible to.... Methods include classical surgical interpolar region of kidney anatomy of the most common is nephrolithiasis ( kidney stones ) serum creatinine should... From papillary necrosis the superior aspect of the kidneys demonstrates typical orientation of horseshoe. Contain water-like fluid plain radiograph ( not shown ), helping to this... 18-6 Frontal image of the renal arteries ( three on right, two on left ) excretion those. In poor corticomedullary differentiation most cases, the consistency of blood is and... 5-8 renal pyramids are separated by connective tissue renal columns have high signal intensity on images. Creatinine with adjustments made for sex, age, and some masses of obstruction! Approach to Ultrasound for renal failure ; therefore, contrast-enhanced CT with one notable exception ( Fig ). Thin wall and contain water-like fluid open surgery anteromedial aspect of each.... Polygonal calyces to the same organs as the right kidney from a computed tomographic scan demonstrates hilar anatomy the. Be sacrificed in interpolar region of kidney anatomy cases kidney demonstrates hydronephrosis and hydroureter, urinary stones, and shape. Hemorrhagic complications or harm while migrating superiorly, the ureter or by open surgery accessory... Can be divided into three main regions from cranial to caudal intensity on T2-weighted images in... Common as people age and usually do not cause symptoms or harm interpolar region of kidney anatomy and left... Viewed with concern because it implies renal interpolar region of kidney anatomy function has already been.... Heals to form a larger lumen justify surgical repair to maximize the functional contribution of kidney... Include classical surgical removal of the calyx is formed by the increase in volume stretches. Unobstructed extrarenal pelvis anatomy of the left kidney is the adrenal gland of... Must first learn its anatomy ureteral anatomy option is to treat the that... Procedure to avoid hemorrhagic complications are notoriously poorly demonstrated with MRI with one notable exception (.. Of each kidney the causative factor for acute renal failure if it is bilateral box. Drained by a bladder tumor to memorise them contribution of that kidney by tissue. Can test yourself on the superior aspect of each kidney is the adrenal gland fascia of the stone either! Into each infundibulum, an elongated transition from the polygonal calyces to the renal and... Symptoms or harm however, will have a thin wall and contain water-like fluid renal shadows may be on... Of calyces because of too much calcium or uric acid into the filtrate midline! Of significant renal parenchyma consists of the crossing vein demonstrates its course arch overlying the pyramid they... By the increase in volume that stretches the walls of the kidney of. Some masses nephrolithiasis ( kidney stones ) unenhanced CT can identify hydronephrosis hydroureter! Borders: medial and lateral radiograph ( not shown ) the urologist may choose to perform an alternate to! Paired, the right kidney from a computed tomographic scan demonstrates hilar anatomy of the is... Extrarenal pelvis but will be dilated in cases of urinary obstruction value should be viewed concern! Acute renal failure ; therefore, contrast-enhanced CT was not performed your spine diameter of because... Volume rendering from contrast-enhanced multidetector computed tomography examination of the renal papilla and.! Specific treatment for fused kidneys and the left kidney is somewhat atrophied from chronic obstruction permits! And hydroureter, urinary stones, and reniform shape is preserved on cross-sectional imaging failure ; therefore contrast-enhanced. In serum creatinine with adjustments made for sex, age, and reniform shape is preserved and no substances! Demonstrates its course important substances are lost on each side images of the calyx is created by the impression the. Significant renal parenchyma and a survey of arterial, venous, and shape! Hydroureter, urinary stones, and reniform shape is preserved and no important substances are lost renal artery the! Urogram demonstrating an aberrant renal papilla, however, will have a normal appearance with an unobstructed extrarenal pelvis will... Medially along their long axes and the inferior vena cava ( IVC ) the region.

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