Kidney : Anatomy and Clinical Significance
Introduction : Kidneys are a pair of retroperitoneal [covered only on anterior side by peritoneum] organs which are part of excretory system. Location : Situated on the posterior abdominal wall behind the peritoneum, one on each side of vertebral column . It covers epigastric , hypogastric ,lumbar and umbilical regions of abdomen . In vertical view : It covers upper border of 12th Thoracic vertebrae [T12] to center body of 3rd Lumbar vertebrae. NOTE : Right kidney is lower than the Left kidney due to presence of liver on right side . The transpyloric line pass through the upper part of hilus of right kidney and lower part of hilus of left kidney respectively. General Features of Kidney: : External Features of Kidney : It consists of : 2 poles : 2 surfaces : NOTE : It is difficult to recognize anterior and posterior surfaces of kidney . 2 borders : structures coming in and going out of the hilum from anterior to posterior side . Some times , Renal artery may enter hilus behind Renal pelvis and Renal vein tributary may also found in same plane that of renal pelvis. Relations Of Kidney : Relations common in both kidney . Other relations of kidneys : Right kidney : NOTE : Left kidney: NOTE: Coverings of kidney [Capsules] : There are 4 coverings of kidney : Fibrous capsule : It is thin membrane ,closely associate with kidney and lines renal sinus . It is smooth and convex . It can be easily stripped off. But in certain diseases it becomes adherent and cannot stripped off. Perirenal or Perinephric fat : It is a adipose tissue which lines the fibrous capsule ,and it is thickest at borders of kidney and fills up extra space in the renal sinus. It extends over adrenal gland superiorly. Nephroptosis [Floating kidney] : It is the condition in which the absence of perirenal fat or seen in severe loss of weight. Renal Fascia [Gerota’s fascia] : It surrounds the perirenal fat and suprarenal glands [Adrenal gland] . This renal fascia is divided into 2 layers : A number of trabeculae connect the renal fascia to fibrous capsule across perirenal fat. Position of renal fascia : TRACED ABOVE : Two layers meet at the upper pole of kidney and split to enclose suprarenal gland and meet again at upper pole of suprarenal gland continue with fascia covering diaphragm. TRACED BELOW : These two layers remain separate and encloses ureter : LATERALLY: Laterally these layers fuses together and continued with the fascia taransversalis behind colon. MEDIALLY : Pararenal fascia : It is present dorsal to renal fascia , this is more on posterior side to fill paravertebral space and acts cushion. Internal structure of kidney : CORTEX : It consists of two parts : MEDULLA : It is made up of conical masses called renal pyramids 10 in number in each kidney . These form renal papillae at apices and these indent minor calyces which give rise to major calyces and then into renal pelvis . RENAL SINUSES : This is the space extends into kidney from the hilus . It contain RENAL PELVIS : This part gives rise to 2 to 3 major calyces and these give rise to 7 to 13 minor calyces. these minor calyces ends in an expansion which intended by 1 to 3 renal papillae . Structure Of Uriniferous Tubule There are 1 to 3 million tubules in each kidney . These are the structural and functional units of kidney. Each tubule consists of two parts : Excretory part : This part of tubule is called as nephron Collecting part : This is the part where all filtrate finally reaches , this is called as Collecting duct . Many collecting ducts unite and form Ducts of bellini which opens into minor calyces through renal papillae. Juxta Glomerular Apparatus The Juxtaglomerular Apparatus (JGA) are specialized structures in the kidneys that plays a critical role in regulating blood pressure, filtration rate, and electrolyte balance. It is located near the junction of the afferent arteriole and the distal convoluted tubule (DCT) of a nephron. The JGA helps maintain homeostasis, particularly by controlling the renin-angiotensin-aldosterone system (RAAS), which regulates blood volume, blood pressure, and sodium balance. Components of the Juxtaglomerular Apparatus: Blood supply : Vascular Segments : BLOOOD SUPPLY : Lymphatic Drainage : Clinical anatomy NOTE : Kidney stones lie on the body of vertebrae and Gall stones lie on anterior to body of vertebrae. Conclusion: In conclusion, the kidneys are vital organs with critical functions in maintaining the body’s internal balance, including waste filtration, fluid and electrolyte regulation, Control blood pressure , and hormone production. Their clinical anatomy, which involves their structure, location, and functional components, is essential for understanding the mechanisms underlying kidney function and the pathophysiology of kidney diseases. The kidneys’ anatomical features, such as the renal cortex, medulla, nephrons, and blood supply, are closely tied to their physiological roles. Knowledge of kidney anatomy is crucial for diagnosing conditions like chronic kidney disease, acute kidney injury, and kidney stones, as well as for performing medical procedures like biopsies, dialysis, and transplantation. Additionally, understanding congenital and developmental kidney anomalies aids in early diagnosis and management. Overall, understanding of the kidneys’ anatomy and clinical relevance is fundamental in preventing, diagnosing, and managing renal diseases, ensuring better patient outcomes and quality of life. References for more details Websites Books Our Other articles
