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1. RENAL-ANATOMY
DR ANEES S PUTHAWALA

2. SURGICAL ANATOMY:
The kidneys are paired organs
lying retroperitoneally
on the posterior abdominal wall
In adults: LK is slightly larger
Adult male kidney weighs approx 125 to 170 g; it is10 to 15 g smaller in females
Superior pole width > Inferior pole width
(mean - 6.48 cm) (mean - 5.39 cm)
Statistically significant correlation b/w renal length & the stature of the person
Mean length Mean thickness at
hilum
Left Kidney 11.21 cm 3.37 cm
Right Kidney 10.97 cm 3.21 cm

3. • The kidneys lie oblique over the psoas major
• Superior pole – medial & posterior
• The hilum is rotated anteriorly,
hilum is angled 30-50⁰ with the horizontal plane
• The lateral border is rotated posteriorly

5. The right kidney sits 1 to 2 cm lower than the left kidney.
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.
Kidneys move inferiorly approximately 3 cm (one vertebral body) during inspiration and
during changing body position from supine to the erect position.
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.

6. Coverings of the Kidney:
1. True fibrous capsule
2. Renal fascia/Gerota’s fascia – ant,post layers
- contain perirenal fat, adrenal gland, kidney,upper ureter
3 potential spaces:
1. Posterior pararenal space – fat
2. Intermediate perirenal space
3. Anterior pararenal space – continuous across the midline
contains the ascending & descending colon, duodenal loop,
pancreas

7. The two layers of the renal
fascia fuse above the
suprarenal gland and end
fused with the infra-
diaphragmatic fascia

8.  Laterally, the two layers of the renal fascia fuse behind the ascending and descending colons.
 Medially, the posterior fascial layer is fused with the fascia of the spine muscles.
 The anterior fascial layer merges into the connective tissue of the great vessels (aorta and inferior vena cava)

10. Relationship Of Kidneys To The Diaphragm
 The posterior surface of the diaphragm attaches to the extremities of the 11th and 12th ribs.
 Close to the spine, the diaphragm is attached over the posterior abdominal muscles, and forms the medial and lateral
arcuate ligaments on each side.
 In this way, the posterior aspect of the diaphragm (posterior leaves) arches in a dome above the superior pole of the
kidneys, on each side.

11. Relationship With
Pleura
 the posterior reflection of the pleura extends inferiorly to the 12th rib
 the lowermost lung edge lies above the 11th rib (at the 10th intercostal
space)
Regardless of the degree of respiration (mid or full expiration), the risk of
injury to the lung from a 10th intercostal percutaneous approach to the
kidney is prohibitive.
Any intercostal puncture should be made in the lower half of the
intercostal space, in order to avoid injury to the intercostal vessels above.

12. Relationship of kidneys to the liver and
spleen
Liver on the right side and the spleen on the left may be
posterolaterally positioned at the level of the suprahilar region
of the kidney

13. Relationship with the colon:
 hepatic flexure  anterior to LP of right kidney
 Splenic flexure  anterolateral to the left kidney
 the retroperitoneal colon has been observed to lie in a posterolateral or even a retrorenal position on CT images making the
colon more prone to injure during the puncture.
 A retrorenal colon is more common in the area of the inferior poles
 Incidence of retrorenal colon – related to patient position: Prone position – 10%. Supine position – 1.9%

15. RIGHT KIDNEY
oThe right kidney is related superiorly to the liver (intraperitoneal and retroperitoneal bare portions) and
superomedially to the adrenal gland.
o Inferiorly, the right kidney is related to the small intestine and hepatic flexure of the colon,
medially it is related to the second part of the duodenum and head of the pancreas.
oThe parietal peritoneum bridging the upper pole of the right kidney to the liver forms the hepatorenal
ligament.
oTherefore excessive downward traction of the right kidney may cause capsular tear of the liver and may
lead to excessive intraoperative bleeding

16. LEFT KIDNEY
o The left kidney is related to the stomach and spleen superiorly,
o adrenal gland superomedially,
o jejunum and splenic flexure of the colon inferiorly, and tail of the pancreas with splenic vessels
medially.
o The parietal peritoneum bridging the upper pole of the left kidney to the spleen forms the splenorenal
ligament. If excessive downward pressure is applied to the left kidney, splenic capsular tears may occur,
leading to hemorrhage from the spleen.

17. To access the kidneys transperitoneally, the colon must be mobilized from the white line of Toldt,
which is the lateral reflection of posterior parietal peritoneum over the ascending and descending
colon.
To access the right renal hilum, the second part of the duodenum and head of pancreas must be
carefully mobilized using the Kocher maneuver.
To access the left renal hilum, the tail of the pancreas together with the spleen and splenic
vessels must be mobilized medially.

18. INTERNAL STRUCTURE OF THE KIDNEY
Each renal pyramid  renal papilla  cupped by
A minor calyx  major calyx  renal pevis
Each kidney and its vessels are surrounded by a
perinephric fat that extends into its hollow vertical cleft,
the renal hilum, which is the entrance to a space
within the kidney called the renal sinus.

19. • Cortex and Medulla
• The renal medulla is formed by several inverted cones,
called the renal pyramid
• Apex of this pyramid is termed the renal papilla.
• The layers of cortical tissue between adjacent pyramids are
termed renal cortical columns of Bertin

20. The cortex made up of the glomeruli with PCT & DCT.
The renal pyramids are made up of loops of Henle and collecting ducts.
Ducts join to form the papillary ducts (about 20), which open at the papillary surface (area
cribosa) and drain urine into the collecting system(into the fornix of a minor calyx).

21. MINOR CALYX
The minor calyces may drain straight into an infundibulum or join to form major calyces
Major calyx will drain into an infundibulum
The infundibula, drain into the renal pelvis

22.  Calyceal fornix- outermost wall of the calyx, into which the papilla is set
 Simple calyx - Only one papilla drains into a minor calyx. The simple calyces usually come in pairs, one facing
anteriorly and one facing posteriorly.
 Compound calyx - two or more papillae entering the calyx. The polar calyces are often compound, markedly in
the superior pole. The compound calyces of the poles of the kidney are oriented facing their respective poles.
 Each kidney - 5 to 14 minor calyces (mean of 8, with 70% of kidneys having 7 to 9 )

23.  Drainage of the upper pole into the renal pelvis is by a single midline infundibulum in most kidneys.
 Drainage from the lower pole is via a single infundibulum in about one half of kidneys and otherwise via a series of paired
anterior and posterior calyces.
 The middle calyces typically are arranged in a series of paired anterior and posterior calyces.

24. Classification of the pelvicalyceal system
(Sampaio)
GROUP A (62.2%)
 2 major calyceal groups (superior and inferior) as a primary division
 Midzone calyceal drainage depends on these major groups
Type A-I (45%)  midzone is drained by minor calyces that are dependent on the superior and/ or inferior calyceal
groups
Type A-II (17.2%)  midzone is drained simultaneously by crossed calyces, one draining into the superior calyceal
group and the other draining into the inferior calyceal group
 The crossed calyces & renal pelvis enclose a space known as interpelvicalyceal region

25. A-I  45% A-II  17.2%

26. GROUP B (37.8%): midzone (hilar) calyceal drainage independent of both the superior and
inferior calyceal groups
Type B‐I (21.4%): midzone drained by a major calyceal group, independent
of both -superior and inferior groups
Type B‐II (16.4%): midzone drained by minor calyces (one to four) entering
directly into the renal pelvis

27. B-I B-II

28. BRODEL’S TYPE (1901) HODSON’S TYPE(1972)
• Posterior calyces – 20o behind frontal plane
• Anterior calyces- 70o in front of frontal plane
• Posterior calyces - lateral
• Anterior calyces –medial
• In most right kidneys
• Just opposite to Brodel’s type
• Calyceal’s pairs rotated posteriorly
• Posterior calyces – 70o behind frontal plane (medial)
• Anterior calyces- 20o in front of frontal plane
• In most left kidneys

41. LYPHATICS

43. NERVE SUPPLY
Sympathetic preganglionic nerves originate from the eighth thoracic through first
lumbar spinal segments, with contributions mainly from the celiac plexus and a
lesser contribution from the greater splanchnic, intermesenteric, and superior
hypogastric plexuses.
Postganglionic sympathetic nerve fiber distribution generally follows the arterial
vessels throughout the cortex and the outer medulla. These postganglionic fibers travel
to the kidney via the autonomic plexus surrounding the renal artery.
In addition, parasympathetic fibers from the vagus nerve travel with the
sympathetic fibers to the autonomic plexus along the renal artery.

44. DROMEDARY/SPLEENIC HUMP
Corresponds to a prominent bulge on the
superolateral border of the left kidney. The
abnormality is best appreciated as an alteration
in left renal contour at US renal contour

45. Renal fetal lobations represent single or
multiple notches of renal profile.
Persistent fetal lobations can be identified in
approximately 5% of
adult patients undergoing renal imaging.

46. Hypertrophied column of Bertin normal renal
cortex projecting into renal sinus, more
frequently at the junction of the upper and
middle third of the left kidney.

47. RADIOLOGICAL ANATOMY

48. Radiograph(X-RAY-KUB)
Both kidney shadows are clearly visible due to the natural
contrast provided by the perirenal fat and can be assessed with
regard to their position and morphology.
The psoas muscle line could also be appreciated; it disappears
with retroperitoneal effusions. Radiopacities, calcifications, and
radiolucencies could be identified

49. IVU
a preliminary plain radiograph of the abdomen from 60 to 90 s after
iodinated contrast agent injection to assess cortical nephrogram
representing contrast material within the tubules.
Then a radiograph on the renal urinary tract is obtained 5–7 min after
contrast injection
Radiograph of the whole urinary tract is obtained 15 min after contrast
Finally, 20–30 min after contract injection, radiographs were
performed on the bladder.

50. USG
• The adult right kidney in the sagittal view demonstrates a cortex that is usually
hypoechoic with respect to the liver.
• The central band of echoes in the kidney is a hyperechoic area that contains the renal
hilar adipose tissue, blood vessels, and collecting system.

51. • In a newborn’s kidneys renal cortex is iso or hyperechoic to liver and spleen
parenchyma, whereas pyramids are more prominent than in adults.
• Neonatal kidneys also show a paucity of renal sinus echoes due to a minimal renal
sinus fat.
• Within 2–6 months, the kidney become progressively less echogenic than the liver
and assume the features of the adult kidney between 6 and 24 months of life.

52. • The thickness of the parenchyma is the average distance between the renal capsule and the
central band of echoes.
• Measurement is subjective.
• The midlateral renal parenchyma in the sagittal view is a common choice for measurement
• The renal cortical thickness should be greater than 7 mm and the renal parenchymal thickness
should be greater than 15 mm in adults

53. Computed tomography (CT)
The renal parenchyma is homogeneous on unenhanced CT with a density ranging from 30 to 60
HU, which increases up to 80–120 HU after iodinated contrast agent administration
Renal sinus and perinephric fat provide intrinsic contrast for the renal parenchyma appearing
hypodense in comparison to the renal parenchyma

54. Corticomedullary phase
30 to 70 seconds of contrast injection
Nephrographic phase
80 to 120 seconds of contrast injection
Excretory phase
More than 180 seconds of contrast
injection

55. MRI
• T1 and T2 relaxation sequences provides information regarding lipid or fat
content and enhancement characteristics of tissues.
• T1-weighted sequences show the renal cortex much brighter than the renal
medulla, whereas the cortex is slightly less intense than the medulla on T2-
weighted sequences.
• The renal pelvis containing fat appears hyperintense on T1- and T2-weighted
sequences

56. corticomedullary phase nephrographic phase
excretory phase

57. Contrast Enhanced Ultrasound of the
Kidneys
ability to detect microvascular blood flow in real time without affecting renal function
composed of gas microbubbles enclosed in a protein, lipid, or polymer shell. This composition
combination allows the agent to be able to last for a certain period of time (in practice up to 5–7
min) inside the blood vessel.
The microbubble diameter ranges from 1 to 10 𝜇m, which is in general the size of a red blood
cell.
As a consequence, these drugs show no extravascular passage and are regarded as pure blood
pool agents.
commonly used agents SonoVue, which consists of stabilised aqueous suspension of sulfur
hexafluoride microbubbles with a phospholipid shell.
The dose for kidney imaging ranges between 1 and 2.4 mL

58. kidneys enhance for a shorter period of time.
The arterial pedicle and main branches pick up the agent first.
After a few seconds, the cortex enhances, followed by medullary perfusion.
The outer medulla fills in earlier, while the pyramids fill in gradually later.
Satisfactory uptake usually lasts for 2min in the kidneys, and subsequently contrast
concentration in circulation decreases and enhancement fades.

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