Renal Anatomy Ch. 1 PDF

▪ The renal system (urinary system) is responsible for filtering out excess fluid and other substances from the blood stream. ▪ Its organs include the kidneys, ureters, bladder, and urethra. ▪ The kidneys are a pair of bean-shaped organs, weighing about 150g. ▪ approximately 12cm long, 6cm in br...

▪ The renal system (urinary system) is responsible for filtering out excess fluid and other substances from the blood stream. ▪ Its organs include the kidneys, ureters, bladder, and urethra. ▪ The kidneys are a pair of bean-shaped organs, weighing about 150g. ▪ approximately 12cm long, 6cm in breadth & 3cm in thickness. ▪ It has: 1. 2 poles; upper and lower. 2. 2 surfaces; anterior and posterior 3. 2 borders; lateral convex and medial concave with a hilum in its middle ▪ The hilum transmits from front backward renal vein, renal artery, and the ureter that is directed downward. ▪ Vein; anteriorly. ▪ Ureter; posterior, directed downwards. ▪ Artery; intermediate – to benefit from its pulsation in improving ureter & venous drainage. MEDOSIS | premium edition 2 Urinary module ▪ They lie: ✓ On the posterior abdominal wall. ✓ Behind the peritoneum ✓ On each side of the vertebral column ▪ They extend from the level of the 12th thoracic vertebra to the level of the 3rd lumbar vertebra. ▪ Upper Pole is 1 inch away from the midline & the lower is 3 inches away ▪ The left kidney lies in an upper position than the right → because of its relation to the liver. ✓ The left kidney reaches up to the 11th rib. ✓ The right kidney reaches up to the 11th intercostal space. ▪ They lie sloping in the para-vertebral gutters → so that the hilum faces somewhat forwards as well as medially. ▪ They lie obliquely with their upper poles nearer to the median plane than the lower ones. MEDOSIS | premium edition 3 Urinary module  ▪ It is composed of an outer cortex and inner medulla. ▪ The medulla consists of conical masses called renal pyramids (10 to 18). ✓ the base of which are directed towards the renal cortex. ✓ their apices (renal papillae) are directed towards the renal sinus. ▪ Minor calyx surrounds one or more renal papillae. ▪ The minor calyces (10 to 12 in number) unit to form 2 or 3 major calyces, which unite forming the renal pelvis inside the renal sinus. ▪ Sinus of the kidney is a central recess within the hilum of the kidney, which contains renal vessels and pelvis. ▪ Cortical tissue extends between the pyramids to form the renal columns. ▪ Each pyramid with its covering cortex forms a renal lobe. Renal Renal cortex parenchyma Renal sinus Renal medulla Renal artery Renal pyramid Renal vein Renal column Renal pelvis Renal Papillae Minor calyx Ureter Major calyx Calcyex MEDOSIS | premium edition 4 Urinary module The kidneys have the following coverings from inside to outside: 1- Fibrous capsule: This surrounds the kidney and is Closely applied to its outer surface. It’s anchored at the hilum and protects it from trauma & infection. 2- Perirenal fat: a layer of adipose tissue that cushions and covers the fibrous capsule. 3- Renal fascia: This is a condensation of connective tissue that lies outside the perirenal fat and encloses the kidneys and suprarenal glands; it is continuous laterally with the fascia transversalis. It lies immediately deep to the parietal peritoneum. 4- Pararenal fat (Renal Bed): This lies external to the renal fascia and is often in large quantity. It forms part of the retroperitoneal fat. “The perirenal fat, renal fascia, and pararenal fat support the kidneys and hold them in position on the posterior abdominal wall.” MEDOSIS | premium edition 5 Urinary module  Relations to the kidney Right kidney Left kidney Anterior relation ✓ Right suprarenal ✓ Left suprarenal gland gland ✓ Stomach ✓ Right lobe of liver ✓ Spleen -pancreas ✓ 2nd part of ✓ Left colic flexure duodenum ✓ Coils of jejunum ✓ Right colic flexure ✓ Coils of jejunum Posterior 12th ribs 11th and 12th ribs relation ✓ Diaphragm ✓ Psoas major muscle ✓ Quadrates lumborum muscle ✓ Subcostal nerve and vessels ✓ Ilio-hypogastric nerve ✓ Ilio-inguinal nerve Anterior relation MEDOSIS | premium edition 6 Urinary module  Posterior relation There is a network of blood vessels throughout the kidneys. ▪ The kidneys receive blood from the aorta via the renal arteries at 2nd lumbar vertebra. ▪ the renal arteries branch into the segmental arteries, the lobar arteries, and the interlobular arteries. ▪ The interlobular arteries branch into the arcuate arteries. ▪ The arcuate arteries branch off into the afferent arterioles. ▪ The afferent arterioles lead into the glomerulus. ▪ Efferent arterioles leave the glomerulus to form peritubular capillaries surrounding the collecting tubules at the renal nephron. ▪ When the blood leaves the nephron it travels to the interlobular veins, the arcuate veins, and then the lobar veins. There are no segmental veins like the segmental arteries. Blood leaves the kidney via the renal veins MEDOSIS | premium edition 7 Urinary module The Kidney represents only 0.4% of the body weight, but it receives 1.2L of blood per minute. The interlobar artery penetrates each renal column, travels between pyramid towards the corticomedullary junction. Renal artery usually gives rise into 5 segmental. based on the distribution of five segmental branches of renal artery, each kidney is divided into five vascular segments: Apical/ superior Upper anterior Middle anterior Caudal/ inferior posterior MEDOSIS | premium edition 8 Urinary module ▪ Each ureter is a long tube of about 10 inches long. ▪ The two ureters are muscular tubes that extend from the kidneys to the posterior surface of the urinary bladder. ▪ The urine is propelled along the ureter by peristaltic contractions of the muscle coat, assisted by the filtration pressure of the glomeruli. ▪ Its upper1/2 lies in the abdomen & its lower 1/2 in the pelvis Course Begins inside the renal sinus as the pelvis of the ureter. The pelvis is the funnel shaped expanded upper end of the ureter. It receives 2,3 major calyces. The ureter emerges from the hilum of the kidney and descends vertically behind the peritoneum, on the psoas major opposite the tips of the transverse processes of the lower 4 lumbar vertebrae. It enters the pelvis by crossing the bifurcation of the common iliac artery in front of the sacroiliac joint. MEDOSIS | premium edition 9 Urinary module  Relations to the ureter Right ureter Left ureter Anterior Medially relation ▪ Inferior vena cava ▪ Inferior mesenteric vein ▪ Inferior mesenteric vein Anteriorly ▪ 2nd part of the duodenum ▪ Left colic vessels. ▪ Right colic vessels ▪ Left gonadal vessels ▪ Gonadal vessels ▪ sigmoid colon ▪ Iliocolic vessels ▪ Sigmoid mesocolon ▪ Root of the mesentery Posterior ▪ Psoas major muscle relation ▪ Genitofemoral nerve ▪ Bifurcation of common iliac artery Anterior relation MEDOSIS | premium edition 10 Urinary module  Posterior relation Pelvic Ureter Course and relations ▪ It enters the pelvic: ✓ Opposite the sacroiliac joint. ✓ Crossing in front of the bifurcation of common iliac artery ▪ Its course is divided into 3 parts. 1) From the pelvic brim to the ischial spine: ▪ It passes downwards and backwards along the anterior margin of greater sciatic foramen. ▪ It crosses the following from above downwards: ✓ External iliac vessels. ✓ Superior vesical artery & obliterated umbilical artery. ✓ Obturator nerve & vessels. ✓ Inferior vesical artery. ✓ Middle rectal artery. ✓ In female forms the posterior border of ovarian fossa. MEDOSIS | premium edition 11 Urinary module From the ischial spine to the urinary bladder: ▪ At the ischial spine the ureter changes its direction to run forwards and medially on the floor of the pelvis to reach the posterosuperior angle of the urinary bladder ▪ In male: It is crossed by the vas deferens ▪ In female: It passes closely lateral to the upper end of vagina. It is crossed by the uterine artery from lateral to medial. 2) Intramural part of the ureter: ▪ It runs a very oblique course through the bladder wall to open at the supra-lateral angle of the trigone. Constrictions of the ureter Along its course it has 3 constrictions: 1. At the pelvi-ureteric junction. 2. As it crosses the pelvic brim. 3. As it pierces the bladder wall (intramural part). ➔ Those Constricted areas are potential sites of obstructions by ureteric stones (calculi) MEDOSIS | premium edition 12 Urinary module Arteries: The ureter is supplied along its course as follows: ▪ Abdominal aorta, renal, gonadal, common iliac & Internal iliac arteries. ▪ Inferior vesical and middle rectal arteries in males. ▪ Twigs from the vaginal and uterine arteries in females. Veins: corresponds to the arteries. Lymph Drainage: The lymph drains to the lateral aortic nodes and the iliac nodes. The nerve supply is the renal, testicular (or ovarian), and hypogastric plexuses (in the pelvis). Afferent fibers travel with the sympathetic nerves and enter the spinal cord in the 1st and 2nd lumbar segments. So, stones will make referred pain in (testis or inguinal region). MEDOSIS | premium edition 13 Urinary module