Gross Anatomy: Kidney, Ureter & Suprarenal Gland PDF 2024

Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 1 of 18 Dr. Dennis Goebel LEARNING OBJECTIVES 1. Describe the kidney: general functions, anatomical features, renal pelvis, renal fascia and fat tissue layers. 2. Describe the anatomical relationships of...

Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 1 of 18 Dr. Dennis Goebel LEARNING OBJECTIVES 1. Describe the kidney: general functions, anatomical features, renal pelvis, renal fascia and fat tissue layers. 2. Describe the anatomical relationships of the kidneys to surrounding structures. 3. Describe the arterial supply and venous/lymphatic drainage of the kidneys. 4. Describe the ureter: its course, anatomical relationships, constriction sites, and blood supply. 5. Describe the innervation of the kidney and ureter. 6. Describe the suprarenal glands: functions, anatomical relationships, arterial supply, venous drainage, and innervation. 7. Apply anatomical knowledge to clinical problems affecting the kidney. Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 2 of 18 Dr. Dennis Goebel SESSION OUTLINE I. Kidney A. Functions B. Anatomy of the kidney 1. Anatomical positioning of the right and left kidney 2. The hilum of the kidney 3. Renal parenchyma a. Renal cortex b. Renal medulla C. Renal pelvis 1. Major and minor calyces 2. Transition of the renal pelvis into the ureter D. Renal fascia and fat tissue layers 1. Renal fascia a. Defining the perinephric space and contents b. Significance of the perinephric space d. Contents of the perinephric space e. Perirenal fat f. Pararenal fat II. Anatomical relationships of the kidneys A. Right kidney B. Left kidney III. Blood supply to the kidney A. Right and left renal arteries 1. Anatomical relationships of the right and left renal arteries and significance of the segmental branches B. Renal veins 1. Anatomical relationships of the renal veins to the renal arteries 2. Anatomical relationships of the left renal vein and tributaries 3. Anatomical relationships of the right renal vein C. Defining the functional lobes of the kidney 1. Significance of the renal segmental arteries D. Lymphatic drainage of the kidneys IV. The ureter A. Course and anatomical relationships of the right and left ureter B. Constriction sites in the ureter C. Ureteric blood supply and significance V. Innervation of the kidney and ureter A. Vasomotor/sympathetic input to the kidney B. Parasympathetic input to the kidney C. Sensory afferents D. Sensory afferents to the kidney E. Sensory regional afferents to the ureter F. Referred pain progression of the ureter VI. Suprarenal glands A. Regional functions of the suprarenal gland Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 3 of 18 Dr. Dennis Goebel 1. Adrenal cortex 2. Adrenal medulla B. Anatomical relationships of the right and left suprarenal glands C. Suprarenal arteries 1. Origin of the superior suprarenal artery 2. Origin of the middle suprarenal artery 3. Origin of the inferior suprarenal artery D. Suprarenal vein 1. Anatomical relationship of the left suprarenal vein 2. Anatomical relationship of the right suprarenal vein E. Innervation of the suprarenal glands 1. Sympathetic innervation of the suprarenal cortex 2. Sympathetic innervation of the suprarenal medulla VII. Clinical relevance A. Horseshoe kidney B. Eptopic kidney C. Renal artery stenosis D. Accessory renal arteries E. Kidney transplantation F. Addison’s disease Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 4 of 18 Dr. Dennis Goebel I. KIDNEY A. Functions 1. Production of urine 2. Endocrine functions a. Releases rennin for angiotensin system b. Releases erythropoietin, which directs hemopoietic stems into proerythroblasts B. Anatomy of the kidney 1. Anatomical positioning: The kidneys (usually 2) are bean-shaped, extraperitoneal (i.e. located posterior to the peritoneal cavity) organ that is surmounted by a suprarenal gland. a. Its posterior surface contacts the diaphragm superiorly, and the psoas major, quadratus lumborum and the aponeurosis of the transversus abdominis inferiorly. b. The superior poles of the right and left kidney are (usually) on a level with the 12th and 11th ribs, respectively; with both kidneys extending inferiorly to the level of LV3. See Figure 1. Figure 1: N308a c. The hilum is a vertical, medial fissure through which, blood vessels, nerves, and the renal pelvis enter or exit the kidney. Lateral to the hilum, these structures Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 5 of 18 Dr. Dennis Goebel pass through a fat-filled cavity within the kidney called the renal sinus (See Figure 2). 2. Renal parenchyma a. The renal cortex is a granular appearing tissue located beneath the fibrous capsule. Continuous with the renal cortex are the renal columns. They extend inward between the renal pyramids of the renal medulla (See Figure 2). b. The renal medulla is composed of eighteen to twenty-two cone-shaped renal pyramids whose bases are outwardly directed. The apex of a renal pyramid is called a renal papilla (Figure 2). a. Figure 2: N311a & c C. Renal calices and renal pelvis of the kidney 1. Each renal papilla is individually capped by a minor calyx (Figure 2), which extends into the renal sinus of the kidney. Three- to four-regional minor calices then merge to form one of three major calices (Figure 2). 2. The three major calices then merge to form the renal pelvis within the renal sinus (Figure 2). 3. Exiting the kidney medially, the renal pelvis narrows near the inferior pole of the kidney and transitions into the ureter (See Figure 2). 4. The ureter then descends, as an extraperitoneal structure, on the anterior surface of the psoas major and passes posterior to the testicular/ovarian vessels. It then courses anterior to the bifurcation of the common iliac artery and then makes a sharp bend over the pelvic brim and courses to the bladder in the floor of the pelvis. Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 6 of 18 Dr. Dennis Goebel D. Renal fascia and fat tissue layers 1. Renal fascia (rt & left) is composed of a membranous connective tissue layer that separately invests each kidney, ureter and suprarenal gland. Each renal fascia merges medially with the adventitia of the renal vessels; superiorly (above the hilum). The fascial layers (ant & post.) of each renal fascia fuse with each other lateral to the kidney. Inferior to the hilum of the kidney, the renal fascial invests the connective tissue surrounding the ureter all the way down to where the ureter empties into the urinary bladder. a. The renal fascia creates a pair (right and left side) of enclosed spaces called the perinephric space (rt & left) that contains the structures listed above, as well as an organized layer of adipose tissue called perirenal fat that invests the kidney, and the ureter, all the way to the urinary bladder (See Figure 3). Figure 3: N315a b. The right and left perinephric spaces do not communicate across the midline. Thus, any infection or hemorrhaging from structures contained by the renal fascia, will be contained by the renal fascia. Note, even though contained by this fascia, the spread of infection or hemorrhaging within this space has an unobstructed path from the kidney/suprarenal glands, all the way down into the pelvis. c Within the perinephric space, there is a thin fascial septum (derived from the renal fascia) that separates the suprarenal gland from the superior pole of the Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 7 of 18 Dr. Dennis Goebel kidney. This has clinical significance in the surgical removal of a kidney, as it provides a dissectible physical barrier between the kidney and the super renal gland, and allows for the suprarenal gland to avoid being damaged during this procedure. d. Contents of the perinephreic space include: The (rt or left) kidney/ureter, the suprarenal gland, the renal- suprarenal and ureteric arteries and veins, and perirenal fat. See Figure 3. i. Perirenal fat: Defined as adipose tissue located between the fibrous capsule of the kidney and the renal fascia surrounding the kidney/ureter. Note, perirenal fat is continuous with the fat extending into the renal sinus of the kidney. e. Pararenal fat: Defined as adipose tissue located external to the renal fascia. The pararenal fat is covered by parietal peritoneum anteriorly and transversalis fascia posteriorly, and invests the renal fascia surrounding the kidney, suprarenal glands, and ureter. See Figure 3 on previous page. II. ANATOMICAL RELATIONSHIPS OF THE KIDNEYS A. Right Kidney: 1. Anterior surface: Liver (upper half of kidney), the hepatic flexure of the colon (lower third of kidney), the 2nd part of the duodenum (covers the hilum and renal pelvis of the kidney), the small intestine (inferior pole of the kidney), and the suprarenal gland, (See Figure 4 on the next page). 2. Posterior surface: 12th rib, thoracic diaphragm, aponeurosis of transversus abdominis, quadratus lumborum, and the psoas major (See Figure 5 on the next page). B. Left kidney: 1. Anterior surface: Stomach, spleen, pancreas, splenic flexure of the colon and jejunum, and the suprarenal gland (See Figure 4 on the next page). 2. Posterior surface: 11th & 12th ribs, thoracic diaphragm, aponeurosis of transversus abdominis, quadratus lumborum, and the psoas major (See Figure 5 on the next page). Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 8 of 18 Dr. Dennis Goebel IVC Figure 5: N309b Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 9 of 18 Dr. Dennis Goebel III. BLOOD SUPPLY TO THE KIDNEY A. Right and left renal arteries 1. The right renal artery is longer than the left, and courses posterior to the inferior vena cava (IVC). See Figures 5 on the previous page, and also illustrated in Figure 8 on the next page. 2. The renal arteries course laterally from the aorta, at the level between LV1-LV2, and are positioned posterior to their corresponding renal veins. Before entering the hilum of the kidney, the renal arteries divide into 5 segmental branches (Figure 7). a. The segmental branches enter the hilum and make their way into the renal sinus, passing on either side of the renal pelvis. In the renal pelvis, each segmental artery divides further before penetrating the kidney parenchyma of the kidney (See Figures Figure 6 & 7). 3. Functional lobes of the kidney are defined by the segmental arteries of the kidney: There are 5 lobes for each kidney, (Figure 7). Each segmental artery supplies a separate lobe of the kidney (Figure 7). a. It is important to note, that there are no anastomotic connections made between the segmental arteries of the kidney. b. Obstruction/blockage of a segmental artery will result in complete loss of the lobe that it supplied. Figure 7: N312 a & b Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 10 of 18 Dr. Dennis Goebel B. Renal Veins 1. The right and renal left veins course anterior to their corresponding arteries, with each draining into the inferior vena cava (See Figure 6). Like the renal arteries, there are 5 renal veins (one from each lobe of the kidney), which converge to from the renal vein. 2. Unique characteristics between the right and left renal veins a. The left renal vein is the longer of the two veins, and courses posterior to the body of pancreas and inferior to the superior mesenteric artery, prior to crossing anterior to the abdominal aorta, before draining into the inferior vena cava (IVC). See Figure 6. i. Tributaries of the left renal vein include the left suprarenal vein and left testicular/ovarian vein (gonadal vein). See Figure 6. b. The short right renal vein courses posterior to the descending part of the duodenum and the head of the pancreas, and drains directly into the inferior vena cava. Note, that the right suprarenal and the right gonadal veins usually enter the inferior vena cava directly. See Figure 6. C. Lymphatic’s from the kidneys and suprarenal glands drain into lumbar nodes, which flow via the lumbar trunks into the cisterna chili. Figure 6: N310 Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 11 of 18 Dr. Dennis Goebel IV. The Ureter A. The left and right ureters are smooth muscular tubes that begin at the narrowing of the renal pelvis and terminate at the bladder. Both ureters are extraperitoneal structures contained within the perinephric space. They course on the anterior surface of the psoas muscle in the abdominal cavity, and crosses anterior to the common iliac arteries before entering the pelvis. There, they are both crossed anteriorly by the gonadal artery (ovarian or testicular) and vein. Note also, that the left ureter is crossed anteriorly by the inferior mesenteric artery and vein (See Figure 8 on the next page). B. Constriction sites in the ureter: There are three internal constriction sites within the ureter. These are common sites where kidney-stones can get lodged. They are located where: 1. The renal pelvis transitions to the ureter. 2. The ureter crosses the common iliac artery 3. The ureter enters the bladder. C. Ureteric blood supply (Figure 8 see on the next page): Blood supply to the ureter is derived from multiple sources. Note: Anastomotic connections with neighboring branches are often incomplete. 1. Local arterial supply to the ureter: See Figure 8 a. Renal arteries: Supply the proximal 5-7 cm of the ureter. Figure 8: b. Abdominal aorta c. Gonadal arteries d. Common and internal iliac braches. e. Branches from the superior vesical (male & female) and inferior vesical (male). These will be detailed in a later module. Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 12 of 18 Dr. Dennis Goebel V. INNERVATION OF THE KIDNEY AND URETER (See Figure 9): A. Sympathetic input to the kidney: 1. The Aorticorenal ganglion (paired) are located on the anterior surfaces of the right and left renal arteries. They receive preganglionic sympathetic fibers from their respective Aorticorenal lesser and least ganglion splanchnic nerves. Postganglionic sympathetic fibers from the aorticorenal ganglion course on the renal artery (and its branches). These nerves function to increase sodium and water resorption by the kidney. Details will be covered in renal physiology lectures. B. Parasympathetic innervation/function to the kidney: According to recent studies, there is no evidence of parasympathetic innervation to the kidney. C. Sensory afferents of the kidney travel with the lesser and least splanchnic nerves and relay visceral pain. See section E for details. D. Innervation to the ureter: 1. Sympathetic Innervation: Preganglionic sympathetic fibers from the least splanchnic (T12), and lumbar splanchnics (L1-L2) synapse on postgangionic neurons in the rt. & left aorticorenal ganglia (associated with the renal arteries). Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 13 of 18 Dr. Dennis Goebel a. Post-ganglionic sympathetic fibers serve to increase ureteric peristalsis when stimulated (See Figure 10 on the next page). 2. Parasympathetic Innervation: Parasympathetic innervation to the ureters are provided by sacral splanchnics (S2-S4). These fibers also stimulate peristalsis of the ureter. Note, the mechanism(s) coordinating sympathetic and parasympathetic peristalsis of the ureter is still not fully understood. 3. Referred pain from the ureter: Sensory afferents travel back to the spinal cord via the lesser (T10-T11) and least splanchnic (T12) N’s, as well as from lumbar splanchnics (L1 & L2). a. Pain, resulting from an infection or a lodged kidney stone within the renal pelvis/kidney is referred to the dermatomes T10-T12 (via, lesser and least splanchnic N.s), along the posterior costal margin (area colored blue in Figure 10). b. As the stones progress through the ureter, irritation or obstruction caused by the stone, will refer pain sensations to dermatomes covered by the iliohypogastric and the ilioinguinal nerve dermatome (L1) (See Figure 11). When the stone reaches the inguinal region, referred pain is then relayed by dermatome corresponding to the genitofemoral N (L1-L2), which is perceived in the groin region (See Figure 11). Figure 10: N321a Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 14 of 18 Dr. Dennis Goebel i. Clinical Significance: “Classic symptoms” for passage of a kidney stone through the ureter begins with pain/ache sensations associated with the lateral surface of the lower costal region (T10 dermatome). If the stone is large enough, its progression down the ureter will be describe by your patient as an intense slow-moving-pain progressing inferiorly on the anterior abdominal wall, in a lateral-to-medial direction (e.g., from the iliac crest towards the pubic region). As the stone approaches the bladder, pain is referred to the inguinal region via of the genitofemoral N. (dermatomes L1-L2) (See pink-colored, Figure 11). Referred pain for left kidney and ureter Kidney T10-T12 Ureter (T12) L1-L2 Image from: Learning Urology Online Figure 11 fitweb.uchc.edu Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 15 of 18 Dr. Dennis Goebel VI. Suprarenal glands A. Relationships: The pyramidal shaped right and left suprarenal glands (SRG) are extraperitoneal organs that are positioned off of the superior poles of their corresponding kidney (Figure 12 on the next page). 1. The SRG’s are located in the perinephreic space (e.g., invested by perirenal fat and contained by the renal fascia), and are separated from the kidney by a thin renal facial layer. 2. The right SRG is related to the inferior vena cava laterally, and to the right lobe of the liver posteriorly, while the left SRG is related to the aorta laterally. B. Regional anatomy and function of the Suprarenal glands 1. The suprarenal cortex (paler, outer region) contains endocrine cells and are essential to life. a. Release mineralocorticoids for H2O and electrolyte balance. b. Release glucocorticoids for carbohydrate metabolism. c. Release sex hormones. 2. The suprarenal medulla is darker stained due to melanin accumulation in the secretory cells and release: a. Releases epinephrine to increase heart rate. b. Releases norepinephrine to increasing blood pressure, by stimulatining vasoconstriction of blood vessels. c. Activated under “fight or flight response” C. Suprarenal arteries: There are three separate arteries that supply each SRG (See Figure 12b on the next page): 1. The superior suprarenal arteries (6-10 in number) branch from the inferior phrenic artery and enter the SRG along the superior medial border. 2. The middle suprarenal artery arises from the abdominal aorta superior to the renal artery and enters the left SRG medially. The right suprarenal A. usually passes posterior to the IVC, and enters the right SRG. 3. The right & left inferior suprarenal artery arises from their respective renal artery, and enters the SGR at its inferior border. (See Figure 12a, b on the next page).  Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 16 of 18 Dr. Dennis Goebel D. Suprarenal veins: Each suprarenal gland has a single suprarenal vein. 1. The left suprarenal vein drains into the left renal vein. 2. The right suprarenal vein drains directly into the inferior vena cava (See Figure 12a & b). A: Left SRG B: Right SRG Figure 12: N320a & b E. Innervation of the suprarenal glands: 1. Suprarenal-cortex: Post-ganglionic sympathetic fibers from the celiac ganglion, that are driven by preganglionic fibers from the greater splanchnic N., act directly onto blood vessels in the suprarenal cortex (See Figure 13 on next page). 2. Suprarenal-medulla: Receives direct input from preganglionic sympathetic fibers arising from the greater splanchnic nerve. These preganglionic fibers synapse directly on chromaffin cells (modified postganglionic sympathetic neurons), and facilitate the release of epinephrine and norepinephrine into the blood stream. (See Figure 13 on next page). b. Sensory afferents are absent in the SRG. c. Parasympathetic innervation to the suprarenal glands: Not well understood. VII. CLINICAL RELEVANCE A. Horseshoe kidney: Occasionally during development, as the rt and left kidneys ascend out of the pelvis, they can fuse at midline and be held up (e.g. not making it to the normal anatomical position in the adult) by the inferior mesenteric artery, forming a Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 17 of 18 Dr. Dennis Goebel single “horseshoe shaped” kidney (See Figure 14A below). Note, that the right and left halves of the horseshoe kidney function independently, and maintain a right and left ureter. B. The embryologic development of the kidney begins in the pelvis, and through differential growth, it assumes a position on the posterior abdominal wall. If this fails to occur, pelvic or ectopic kidney(s) can result (See Figure 14B). Inferior Mesenteric Figure 14: Moore 3rd Ed. Fig 2-97 D & E C. Renal artery stenosis: Segmental branches of a renal artery do not anastomose, therefore, obstruction of a segmental artery, or one of its branches, leads to renal infarction and necrosis of the part of the kidney supplied by the artery. D. Accessory renal arteries from the abdominal aorta are present in about 20% of individuals. They usually do not pass through the hilum, but enter the kidney on its extra- hilar surface (Figure 15). Figure 15: N333A (4th Ed.) Gross Anatomy: Kidney, Ureter & Suprarenal Gland Page 18 of 18 Dr. Dennis Goebel E. Kidney transplantation: A donated kidney containing it’s renal artery/vein and ureter, is transplanted into the pelvic region of the recipient, with the blood vessels (renal artery and vein) from the donated kidney being ligated into the hosts common iliac vessels, and the proximal region of the ureter being sutured into the host’s bladder. Transplantation of the kidney into the pelvis is essential for the survival of the transplanted ureter. This is due to the poor arterial anastomotic connections of the ureter. Note: Early kidney transplantation studies found that the donor-kidney’s renal artery only adequately supplies the proximal end of the ureter (roughly the first 7 cm). Distal to this, the ureter will undergo necrosis. Sources for Figures in the notes: Gardner, Gray and O'Rahilly, Anatomy 4th Edition, W.B. Saunders Co., Philadelphia, © 1975. Hollinshead & Rosse, Textbook of Anatomy, 4th Edition, Harper & Row, Philadelphia, © 1985. Mizeres, Human Anatomy: A Synoptic Approach, Elsevier, New York, © 1981. Moore, Clinically Oriented Anatomy, 3 rd Edition, Williams & Willkens, Baltimore, © 1992. Moore & Dalley, Clinically Oriented Anatomy, 4th Edition, Williams & Willkens, Baltimore, © 1999 Netter, Atlas of Human Anatomy, 4th Ed.,Saunders, Philadelphia, © 2006. Netter, Atlas of Human Anatomy, 6th Ed.,Saunders, Philadelphia, © 2014.