ICL 1.0: Embryology and Anatomy of the Kidney Flashcards
(44 cards)
which structures are located next to the kidneys anatomically?
the adrenal glands sit right on top of the kidneys!
the inferior vena cava and abdominal aorta run right inbetween the two kidneys
the kidneys are right at the level of the 11th and 12th ribs –> the right kidney is slightly lower than the left because the liver is on the right side and pushes that kidney down a little
psoas, quadratus lumborum and transversus abdominis muscles surround them as well
what kind of organ is the kidney? how big is it?
it’s a retroperitoneum organ
grossly, the kidneys are 2 organs in the posterior side of the body
150 g male/130 g female
12x10x3 cm each = based on the size, you can predict the function because a small kidney will have less nephrons so less function! also when you’re matching kidney donors, the size matters too
what are the relevant anatomical associations of the right kidney?
- liver
- adrenal gland
- duodenum
- small intestine
- colon
superiorly, there’s the hepatorenal ligament which attaches the right kidney to the liver –> so some injuries to the liver or kidney can shear this attachment and cause significant bleeding
medially, there’s part of the duodenum which is associated with the hilar structures of the kidney – Kocher maneuver moves the duodenum off the kidney so you can see it
the colon is also associated with the kidney so you’d also have to reflect that off – part of the small intestine may or may not be too based on the person
the right adrenal gland sits on top of the kidney
what are the relevant anatomical associations of the left kidney?
- spleen
- stomach
- adrenal gland
- pancreas
- colon
superiorly the left kidney is bordered by the tail of the pancreas and splenic vessels that run posterior to the pancreas
so if someone is getting a left nephrectomy you have to counsel the patient they could get pancreatitis or adrenal injury or splenic injury or even the stomach
what is the gerota fascia?
aka perirenal fascia
it encases the kidney and protects the kidney from infections that could come from other organs
it also limits the invasion of tumors from the kidney or to the kidney
inferiorly, the gerota fascia isn’t closed; so if the kidney has a deep laceration, the blood will pool inferiorly because of this – that also means perinephric fluid collections can track inferiorly into the pelvis without violating gerota fascia
it crosses the midline and fuses with the gerota fascia of the other kidney
what is the renal artery?
they’re inferior to the superior mesenteric artery and originate off the descending aorta
the renal arteries are end arteries so there are no collateral arteries! they end at the parenchyma of the kidneys
the kidney then splits into 5 branches = segmental arteries –> posterior, apical, upper, middle and lower segmental arteries
the renal vein is anterior to the renal artery – then the renal pelvis and ureter are located posterior to both of these vascular structures
what is the most important segmental artery of the renal artery ?
posterior segmental branch
typically the first branch of the renal artery and it passes posterior to the renal pelvis while the rest of the segmental arteries pass anterior to the renal pelvis – sometimes there are anomalies where the posterior segmental branch where it’s anterior and this causes compression of the renal pelvis which would cause a ureteropelvic junction obstruction with a lot of pain and renal function could be compromised
any occlusion of it would cause infarct of that area of the kidney and it’ll become necrotic because there’s no collaterals!!
each segmental artery supplies a distinct portion of the kidney with no collateral circulation between them so occlusion or injury to a segmental branch will cause segmental renal infarction
48 year old presents to the emergency room with sudden onset of severe abdominal pain, 10/10, associated with nausea & vomiting. Patient is afebrile, Bp 85/60, HR 109, RR 28, she is alert and oriented. Reports a history of asthma, depression and kidney problem.
what do you do next?
what type of tumor does she most likely have?
resuscitate and give fluids and get CT scan
CT scan shows bleeding tumor! angiomyolypoma
AML is a benign tumor composed of blood vessels, smooth muscles and fat and they are the most common benign mesenchymal renal tumors!!
the kidney is supplied by end arteries so you can go in and embolize the arteries causing the bleeding; this would treat the tumor!
what is the flow of oxygenated blood through the kidney?
the renal artery originates from the abdominal aorta and becomes the segmental artery which then becomes the lobar artery
then blood goes into the interlobar arteries –> arcuate artery –> interlobular arteries –> afferent arteriole –> glomerulus –> efferent arteriole
go look at the picture; it’s very important!
what is the venous system of the kidney?
the veins have collateral flow unlike the arterial supply, the venous drainage communicates freely through venous collars around the infundibula, providing for extensive collateral circulation in the venous drainage of the kidney
this means that occlusion of the renal vein has little or no effect on renal outflow
the renal vein originates from the abdominal inferior vena cava
the left renal vein receives the left adrenal vein superiorly, lumbar vein posteriorly, and left gonadal vein inferiorly while the right renal vein typically does not receive any branches so the right gonadal and adrenal vein comes off the IVC itself on the right
the right renal vein is shorter which makes sense because the IVC is on the right side of the body so the left renal vein has to travel a little more to get to it
right renal vein doesn’t usually have branches so the gonadal vein on the right side comes right off the IVC
32 year old female presents to your clinic with complaint of gross hematuria. She reports that she started an intensive exercise regimen with 3o pound weight loss during the “covid lockdown”. She feels well overall, except for occasional left flank discomfort and blood in her urine.
what’s wrong?
Nutcracker syndrome = left renal vein compression
superior mesenteric artery originates from the aorta just above the left renal vein - usually there’s a fat pad that separates these two structures but patients who have lost a lot of weight lose this and they get compression of the renal vein! so the SMA is compressing the renal vein between the SMA and the thoracic aorta!
this can cause DVTs!!!
overtime, this blood needs to leave and get back to the heart but if it’s compressed, it’ll go through the collateral veins like the lumbar, gonadal etc. so the collateral veins get very distended
it takes time for these collaterals to develop though so in the meantime you’ll get hemorrhage which shows up as blood in the urine! there’s also distention of the capsule of the kidney which leads to flank pain
what is the renal lymphatic system?
on the left, primary lymphatic drainage is into the left lateral para-aortic lymph nodes including nodes anterior and posterior to the aorta between the inferior mesenteric artery and the diaphragm
occasionally, there will be additional drainage from the left kidney into the retrocrural nodes or directly into the thoracic duct above the diaphragm
on the right, drainage is into the right interaortocaval and right paracaval lymph nodes including nodes located anterior and posterior to the vena cava, from the common iliac vessels to the diaphragm. Occasionally, there will be additional drainage from the right kidney into the retrocrural nodes or the left lateral para-aortic lymph nodes.
how common are anatomic variations in the renal vasculature?
common…
up to 25-40% of kidneys
this is important because lower pole arteries on the right tend to cross anterior to the IVC, whereas lower pole arteries on either side can cross anterior to the collecting system, causing a ureteropelvic junction obstruction
the artery of the right kidney runs posteriorly but if you have an extra artery they’ll run anterior to the IVC which causes a problem because arteries are muscular structures and can cause compression of other structures like the ureter (like with Nutcracker syndrome)
where does the renal collecting system originate from?
the renal collecting system originates in the renal cortex at the glomerulus as filtrate enters into Bowman capsule
what is the innervation of the kidney?
sympathetic preganglionic nerves originate from the eighth thoracic through first lumbar spinal segments and then travel to the celiac and aorticorenal ganglia
parasympathetic fibers originate from the vagus nerve and travel with the sympathetic fibers to the autonomic plexus along the renal artery
the primary function of the renal autonomic innervation is vasomotor, with the sympathetic inducing vasoconstriction and the parasympathetic causing vasodilation
the nerves run along the arteries
so sometimes people with uncontrolled BP get a kidney removed and it helps their BP!
how does the position of the kidney change?
the exactpositionof the kidney within the retroperitoneum varies during different phases of respiration, body position, and presence of anatomic anomalies.
for example, the kidneys move inferiorly approximately 3 cm (one vertebral body) during inspiration and during changing body position from supine to the erect position
because of the inferior displacement of the right kidney by the liver, the right kidney sits 1 to 2 cm lower than the left kidney
therefore the right kidney resides in the space between the top of the 1st lumbar vertebra to the bottom of the 3rd lumbar vertebra, whereas the left kidney occupies a space between the 12th thoracic vertebra and the 3rd lumbar vertebra
what is the ureter?
bilateral tubular structures responsible for transporting urine from the renal pelvis to the bladder
begins at the renal-pelvic junction posterior tot he renal artery and vein; then progresses inferiorly along the anterior border of the psoas muscle
anteriorly, the right ureter is related to the ascending colon, cecum, colonic mesentery, and appendix
the left ureter is closely related to the descending and sigmoid colon and their accompanying mesenteries
approximately a third of the way to the bladder the ureter is crossed anteriorly by the gonadal vessels. As it enters the pelvis the ureter crosses anterior to the iliac vessels. This crossover point is usually at the bifurcation of the common iliac into the internal and external iliac arteries, thus making this a useful landmark for pelvic procedures
what are the different segments of the ureter?
the ureter can be divided into upper, middle, and lower segments
the upper ureter extends from the renal pelvis to the upper border of the sacrum
the middle ureter comprises the segment from the upper to the lower border of the sacrum
the lower (distal or pelvic) ureter extends from the lower border of the sacrum to the bladder
what is the blood supply of the ureter?
it’s segmental
the upper part is from the renal artery and gonadal artery and the aorta itself; these are usually posterior and medial
the middle to lower ureter is all medial supply from the common, internal and external lilac arteries!
if there was a uretopelvic junction obstruction from stricture, you can use a scope and go into the ureter and make an incision to try and open up the ureter!
what are come normal variations in uretal caliber?
- UPJ
- the iliac vessels
- ureterovesical junction
so the ureter has sites of normal functional/ anatomic narrowing at the ureteropelvic junction (UPJ), the iliac vessels, and the ureterovesical junction (UVJ)
there’s also the anterior displacement and angulation of the ureter over the iliac vessels
where does kidney pain present?
anterior pain of the kidney can radiate to the groin
posteriorly it’s in the flank
how is the ureter anatomically related to the male anatomy?
as the ureter enters the bladder it crosses anterior to common ilac artery and dives into the deep pelvis to the bladder
it enters posteriorly to the vas deferens
so when you’re approaching the prostate, you have to be careful not to damage the ureter˜
how is the ureter anatomically related to the female anatomy?
hysterectomy meas uterine artery has to be ligated and the ureter runs right next to it and it could potentially get ligated too! so you have to be careful
summary of kidney anatomy?
The kidney is divided into cortex and medulla. The medullary areas are pyramidal, more centrally located, and separated by sections of cortex. These segments of cortex are called the columns of Bertin.
Orientation of the kidney is greatly affected by the structures around it. Thus the upper poles are situated more medially and posteriorly than the lower poles. Also, the medial aspect of the kidney is more anterior than the lateral aspect.
Gerota fascia envelops the kidney on all aspects except inferiorly, where it is not closed but instead remains an open potential space.
From anterior to posterior, the renal hilar structures are the renal vein, renal artery, and collecting system.
The renal artery splits into segmental branches. Typically, the first branch is the posterior segmental artery, which passes posterior to the collecting system. There are generally three to four anterior segmental branches that pass anteriorly to supply the anterior kidney.
The progression of arterial supply to the kidney is as follows: renal artery → segmental artery → interlobar artery → arcuate artery → interlobular artery → afferent artery.
The venous system anastomoses freely throughout the kidney. The arterial supply does not. Thus occlusion of a segmental artery leads to parenchymal infarction, but occlusion of a segmental vein is not problematic because there are many alternate drainage routes.
Anatomic variations in the renal vasculature are common, occurring in 25% to 40% of kidneys.
Each renal pyramid terminates centrally in a papilla. Each papilla is cupped by a minor calyx. A group of minor calyces join to form a major calyx. The major calyces combine to form the renal pelvis.
There is great variation in the number of calyces, calyceal size, and renal pelvis size. The only way to determine pathologic from normal is by evidence of dysfunction.
