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Kidneys: Difference between revisions

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** '''Renal vascular pedicle'''
** '''Renal vascular pedicle'''
** '''Gonadal vessels'''
** '''Gonadal vessels'''
* '''The perirenal fat is finer and lighter yellow in color compared with the coarser yellow-orange pararenal fat.'''
* '''<span style="color:#ff0000">The perirenal fat is finer and lighter yellow in color compared with the coarser yellow-orange pararenal fat.</span>'''
* '''The perirenal space has a conelike shape that is open at its inferior extent in the extraperitoneal pelvis.'''
* '''The perirenal space has a conelike shape that is open at its inferior extent in the extraperitoneal pelvis.'''
** There is some controversy regarding the medial and inferior extents of the perirenal space. Historically, it was assumed that there was no communication between the right and left perirenal spaces. However, based on in vivo cases and cadaveric injection studies, there may be some communication across the midline below the level of the renal hilum
** There is some controversy regarding the medial and inferior extents of the perirenal space. Historically, it was assumed that there was no communication between the right and left perirenal spaces. However, based on in vivo cases and cadaveric injection studies, there may be some communication across the midline below the level of the renal hilum
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* Named after the Romanian anatomist Dimitrie D. Gerota (1867-1939)
* Named after the Romanian anatomist Dimitrie D. Gerota (1867-1939)
* '''Encloses perinrenal space'''
* '''Encloses perinrenal space'''
* '''Closed superiorly and laterally, and open inferiorly'''
* '''<span style="color:#ff0000">Closed superiorly and laterally, and open inferiorly</span>'''
** Superiorly, the Gerota fascia is continuous with the diaphragmatic fascia on the inferior surface of the diaphragm
** Superiorly, the Gerota fascia is continuous with the diaphragmatic fascia on the inferior surface of the diaphragm
** '''The anterior and posterior laminae merge laterally to form the lateroconal fascia, which functions to separate the anterior and posterior pararenal spaces.''' It can be visualized radiographically on computed tomographic (CT) scan and continues anterolaterally deep to the transversalis fascia.
** '''<span style="color:#ff0000">The anterior and posterior laminae merge laterally to form the lateroconal fascia,</span> which functions to separate the anterior and posterior pararenal spaces.''' It can be visualized radiographically on computed tomographic (CT) scan and continues anterolaterally deep to the transversalis fascia.
***The lateroconal fascia then fuses with the peritoneum lateral to the colon to form the white line of Toldt.
***'''The lateroconal fascia then fuses with the peritoneum lateral to the colon to form the white line of Toldt.'''
** '''Perinephric fluid collection can tract inferiorly into the pelvis without violating the Gerota fascia'''
** '''<span style="color:#ff0000">Clinical implication: Perinephric fluid collection can tract inferiorly into the pelvis without violating the Gerota fascia</span>'''
* '''Continues medially to fuse with the contralateral side'''
* '''Continues medially to fuse with the contralateral side'''
**Envelops the aorta and IVC
**'''Envelops the aorta and IVC'''
* '''Extends inferiomedially along the abdominal ureter as a periureteral fascia'''
* '''Extends inferiomedially along the abdominal ureter as a periureteral fascia'''
* '''Surrounded by a layer of condensed fat called paranephric fat'''
* '''Surrounded by a layer of condensed fat called paranephric fat'''
* Must be opened to access the kidneys, adrenals, or abdominal ureters
* '''Must be opened to access the kidneys, adrenals, or abdominal ureters'''
** To access the kidneys transperitoneally, the colon needs to be mobilized from the white line of Toldt
** To access the kidneys transperitoneally, the colon needs to be mobilized from the white line of Toldt


== Renal hilum ==
== Renal hilum ==


* '''Structures (from anterior to posterior) (4) VAUA:'''
* '''<span style="color:#ff0000">Structures (from anterior to posterior) (4)</span><span style="color:#0000ff"> VAUA:</span>'''
** '''Renal Vein'''
** '''<span style="color:#ff0000">Renal </span><span style="color:#0000ff">V</span><span style="color:#ff0000">ein'''
** '''Renal Artery'''
** '''<span style="color:#ff0000">Renal </span><span style="color:#0000ff">A</span><span style="color:#ff0000">rtery'''
** '''Renal pelvis/Ureter'''
** '''<span style="color:#ff0000">Renal pelvis/</span><span style="color:#0000ff">U</span><span style="color:#ff0000">reter'''
** '''Posterior segmental Artery'''
** '''<span style="color:#ff0000">Posterior segmental </span><span style="color:#0000ff">A</span><span style="color:#ff0000">rtery'''
* '''To access'''
* '''To access'''
** '''Right renal hilum, the second part of the duodenum and head of pancreas need to be mobilized using the Kocher maneuver'''
** '''Right renal hilum, the second part of the duodenum and head of pancreas may need to be mobilized medially to expose the IVC'''
** '''Left renal hilum, the tail of the pancreas together with the spleen and splenic vessels need to be mobilized medially'''
** '''Left renal hilum, the tail of the pancreas and the spleen (with the splenic vessels) need to be mobilized'''


== Gross and microscopic anatomy ==
== Gross and microscopic anatomy ==


* '''The kidney is divided into cortex and medulla'''
* '''The kidney is divided into cortex and medulla'''
* Medulla is more centrally locating and divided into 8-18 striated renal pyramids
* '''Renal Medulla'''
* The base of the pyramids is positioned at the corticomedually boundary
**More centrally located
* Each renal pyramid terminates centrally in a papilla, and each papilla is cupped by an individual minor calyx
**Divided into 8-18 striated renal pyramids
* A group of minor calyces join to form a major calyx. The major calyces combine to form the renal pelvis
*** The base of the pyramids is positioned at the corticomedually boundary
* '''The renal cortex''' is ≈1 cm in thickness and covers the base of each renal pyramid peripherally and '''extends downward between the individual pyramids to form the columns of Bertin'''
*** Each renal pyramid terminates centrally in a papilla, and each papilla is cupped by an individual minor calyx
**** '''A group of minor calyces join to form a major calyx. The major calyces combine to form the renal pelvis'''
* '''Renal Cortex'''
**≈1 cm in thickness
**Covers the base of each renal pyramid peripherally
**'''Extends downward between the individual pyramids to form the columns of Bertin'''
* The cells lining the collecting ducts are cubical to columnar and are more resistant to damage than those of the renal tubules.
* The cells lining the collecting ducts are cubical to columnar and are more resistant to damage than those of the renal tubules.
* The calyces, pelvis, ureters, bladder, and urethra are lined by transitional epithelium/urothelium
* The calyces, pelvis, ureters, bladder, and urethra are lined by transitional epithelium/urothelium
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* Each kidney is commonly supplied by a single renal artery, which arises directly from the abdominal aorta, and a single renal vein usually drains directly to the IVC
* Each kidney is commonly supplied by a single renal artery, which arises directly from the abdominal aorta, and a single renal vein usually drains directly to the IVC
* '''Arterial supply'''
 
** '''Summary of branching:'''
=== Arterial supply ===
*** '''Main renal artery -->'''
* '''Summary of branching:'''
*** '''Anterior vs. posterior branch -->'''
** '''Main renal artery -->'''
*** '''Segmental arteries -->'''
** '''Anterior vs. posterior branch -->'''
*** '''Lobar arteries -->'''
** '''Segmental arteries -->'''
*** '''Interlobar arteries -->'''
** '''Lobar arteries -->'''
*** '''Arcuate arteries -->'''
** '''Interlobar arteries -->'''
*** '''Interlobular arteries -->'''
** '''Arcuate arteries -->'''
*** '''Afferent arteriole -->'''
** '''Interlobular arteries -->'''
*** '''Glomerulus -->'''
** '''Afferent arteriole -->'''
*** '''Efferent arteriole'''
** '''Glomerulus -->'''
** '''Anterior and posterior branch of main renal artery'''
** '''Efferent arteriole'''
*** '''Anterior branch'''
* '''<span style="color:#ff0000">Anterior and posterior branch of main renal artery</span>'''
**** '''Supplies the anterior aspect, comprising ≈2/3 of the total kidney'''
** '''<span style="color:#ff0000">Anterior branch</span>'''
**** '''Divides into segmental arteries (4):'''
*** '''<span style="color:#ff0000">Supplies the anterior aspect, comprising ≈2/3 of the total kidney</span>'''
****# '''Apical'''
*** '''Divides into segmental arteries (4):'''
****# '''Upper'''
***# '''Apical'''
****# '''Middle'''
***# '''Upper'''
****# '''Lower'''
***# '''Middle'''
*** '''Posterior branch'''
***# '''Lower'''
**** '''Supplies the posterior aspect, comprising ≈1/3 of the total kidney'''
** '''<span style="color:#ff0000">Posterior branch</span>'''
**** '''Becomes the posterior segmental artery'''
*** '''<span style="color:#ff0000">Supplies the posterior aspect, comprising ≈1/3 of the total kidney</span>'''
**** '''Represents the first and most consistent branch, which separates from the renal artery before it enters the renal hilum'''
*** '''Becomes the posterior segmental artery'''
**** A small apical segmental branch may originate from this posterior branch, but it arises most commonly form the anterior division
*** '''Represents the first and most consistent branch, which separates from the renal artery before it enters the renal hilum'''
** '''Segmental arteries'''
*** A small apical segmental branch may originate from this posterior branch, but it arises most commonly form the anterior division
*** '''End arteries''' that do not anastomose significantly with other segmental arteries.
* '''<span style="color:#ff0000">Segmental arteries</span>'''
**** '''Occlusion or injury to a segmental branch will cause segmental renal infarctions.'''
** '''<span style="color:#ff0000">End arteries</span>''' that do not anastomose significantly with other segmental arteries.
*** '''The posterior segmental artery from the posterior division passes posterior to the renal pelvis while the others pass anteriorly pass anterior to the renal pelvis'''
*** '''<span style="color:#ff0000">Clinical implication: Occlusion or injury to a segmental branch will cause segmental renal infarctions.</span>'''
**** '''If the posterior segmental branch passes anterior to the ureter, UPJO may occur'''
** '''<span style="color:#ff0000">The posterior segmental artery from the posterior division passes posterior to the renal pelvis while the others pass anteriorly pass anterior to the renal pelvis</span>'''
**** '''There is a longitudinal avascular plane (line of Brodel) between the posterior and anterior segmental arteries just posterior to the lateral aspect of the kidney through which incision results in significantly less blood loss'''
*** '''Clinical implication: If the posterior segmental branch passes anterior to the ureter, UPJO may occur'''
***** Posterior calyces along the line of Brodel are preferred
*** '''There is a longitudinal avascular plane (line of Brodel) between the posterior and anterior segmental arteries just posterior to the lateral aspect of the kidney through which incision results in significantly less blood loss'''
** Variations to renal vascular occur in 25-40% of kidneys
**** Posterior calyces along the line of Brodel are preferred
*** '''Accessory renal arteries are seen in 25-28% of patients''' and are considered the sole arterial supply to a specific portion of the renal parenchyma; '''these may contraindicate laparoscopic donor nephrectomy'''
* '''Variations to renal vascular occur in 25-40% of kidneys'''
*** '''Blood supply to an ectopic kidney originates from adjacent vessels'''
** '''Accessory renal arteries are seen in 25-28% of patients''' and are considered the sole arterial supply to a specific portion of the renal parenchyma
* '''Venous drainage'''
***'''Clinical implication: presence of accessory renal artery may contraindicate laparoscopic donor nephrectomy'''
** '''Correlates closely with the arterial supply, with the exception that venous drainage has extensive collateral communication. unlike the arterial supply'''
** '''Blood supply to an ectopic kidney originates from adjacent vessels'''
** 3-5 segmental renal veins eventually unite to form the renal vein
 
** The right and left renal veins lie anterior to the right and left renal arteries and drain into the IVC.
=== Venous drainage ===
** The right renal vein is 2-4 cm, the left renal vein is 6-10 cm.
* '''Correlates closely with the arterial supply, with the exception that venous drainage has extensive collateral communication. unlike the arterial supply'''
** '''The longer left renal vein receives the left adrenal vein and the left gonadal (testicular or ovarian) vein. The left renal vein also may receive a lumbar vein, which could be easily avulsed during surgical manipulation of the left renal vein.'''
* 3-5 segmental renal veins eventually unite to form the renal vein
** '''The left renal vein traverses the acute angle between the superior mesenteric artery anteriorly'''
* '''The right and left renal veins lie anterior to the right and left renal arteries and drain into the IVC.'''
*** '''Nutcracker syndrome most often refers to compression of the left renal vein between the superior mesenteric artery and aorta'''
* '''<span style="color:#ff0000">The right renal vein is 2-4 cm, the left renal vein is 6-10 cm.</span>'''
*** Insert figure
* '''<span style="color:#ff0000">The longer left renal vein receives the left adrenal vein and the left gonadal (testicular or ovarian) vein.</span>'''
*** '''Anomalies of the renal veins are less common than those of the renal arteries'''
**'''<span style="color:#ff0000">The left renal vein also may receive a lumbar vein,</span> which could be easily avulsed during surgical manipulation of the left renal vein.'''
* '''The left renal vein traverses the acute angle between the superior mesenteric artery anteriorly'''
** '''Nutcracker syndrome most often refers to compression of the left renal vein between the superior mesenteric artery and aorta'''
** Insert figure
** '''Anomalies of the renal veins are less common than those of the renal arteries'''


== Pelvicalyceal system ==
== Pelvicalyceal system ==
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