Kidneys Flashcards
What are the kidneys?
Pair of excretory, retroperitoneal organs
Location of the kidneys
Situated on the posterior abdominal wall, one on each side of the vertebral column, behind the peritoneum
Occupy the epigastric, hypochondriac, lumbar and umbilical regions
Extend from T12 vertebra to L3
Difference in location between right and left kidneys
Right kidney is slightly lower than the left
Left kidney is a little nearer to the median plane than the right
Dimensions of the kidneys
11cm long
6 cm broad
3 cm thick
Weight of kidneys
150g in males
135g in females
Direction of the kidneys
Long axis of the kidney is directed downwards and laterally so the upper poles are nearer to the median plane than the lower poles
What are the poles of the kidneys?
Upper pole: Broad and in close contact with the corresponding suprarenal gland
Lower pole: Pointed
What are the surfaces of the kidneys?
Anterior surface: Irregular
Posterior surface: Flat
What are the borders of the kidneys?
Lateral border: Convex
Medial border: Concave (the middle part has the hilus/hilum)
Constituents of the hilum of the kidney
Anterior to posterior:
Renal Vein
Renal Artery
Renal Pelvis (expanded upper end of the ureter)
Anterior relations of the right kidney
Right suprarenal gland
Liver
Second part of duodenum
Hepatic flexure of colon
Small intestine
Which of the anterior relations of the right kidney are covered by peritoneum?
Hepatic
Intestinal
What are lateral relations of the right kidney?
Right lobe of the liver
Hepatic flexure of the colon
What are the anterior relations of the left kidney?
Left suprarenal gland
Spleen
Stomach
Pancreas
Splenic vessels
Splenic flexure and descending colon
Jejunum
Which of the anterior relations of the left kidney are covered by peritoneum?
Gastric
Splenic
Jejunal
Lateral relations of the left kidney
Spleen
Descending colon
What relations are common to both kidneys?
Upper pole: Suprarenal gland.
Lower poles lie about 2.5 cm above the iliac crests
Medial border of each kidney is related to:
1. Suprarenal gland above the hilus
2. Ureter below the hilus
Most posterior relations are common between both kidneys
What are the posterior relations of the kidneys?
Diaphragm
Medial and lateral arcuate ligaments
Psoas major
Quadratus lumborum
Transversus abdominis
Subcostal vessels
Subcostal, iliohypogastric and ilioinguinal nerves
What additional posterior relations does each kidney have (which aren’t shared between both)?
Right Kidney: Twelfth rib
Left Kidney: Eleventh and Twelfth ribs
What is the fibrous capsule?
Thin membrane which covers the kidney and lines the renal sinus
Can generally be removed easily except in certain diseases
What is perirenal/perinephric fat?
Layer of adipose tissue
Lies outside the fibrous capsule
Thickest at the borders of the kidney and fills up the extra space in the renal sinus
What are the layers of the renal fascia?
Posterior Layer: Fascia of Zuckerkandal
Anterior Layer: Fascia of Gerota
Describe how the renal fascia changes across the kidney
Right side at the level of upper pole of kidney, anterior fascia blends with inferior coronary layer and bare area of liver
Posterior layer on both right and left sides fuses with fasciae of muscles of posterior abdominal wall
Medially, the anterior layer is continuous from one to the other kidney and the posterior layer is attached either side of vertebra
Below, both the layers extend along the ureter and fuse with iliac fascia
What is the pararenal/paranephric body?
Fat lying outside the renal fascia
Where is pararenal fat most common?
Posteriorlty and twoards the lower pole of the kidney
Fills up the paravertebral gutter and forms cushion for kidney
What is the internal structure of the kidney?
Outer-reddish brown cortex
Inner-pale medulla
A space called the renal sinus
What is the structure of the renal medulla?
10 renal pyramids
Apices form the renal papillae which indent the minor calyces
What are the sections of the renal cortex?
Cortical arches or cortical lobules which form caps over the bases of the pyramids
Renal columns which dip in between the pyramids
What structures form a kidney lobe?
Each pyramid and its overlying cortical arch
What is a renal sinus?
Space that extends into the kidney from the hilus
Contents of a renal sinus
Branches of the renal artery
Tributaries of the renal vein
Renal pelvis (which divides into 2-3 major calyces)
Describe the divisions of the renal pelvis
Pelvis divides into 2-3 major calyces
Each major calyx divides into 7-13 minor calyces
Each minor calyx ends in an expansion which is indented by one to three renal papillae
How is exposure of the kidney prepared for?
Resection of 12th rib
What is the risk when resecting the 12th rib?
Danger of opening the pleural cavity (the lower border of the pleura lies between 12th rib and diaphragm)
Anterior to Posterior: Diaphragm, Pleura, Ribs
Where can tenderness of the kidney be elicited?
Applying pressure over the renal angle
What is the renal angle?
Angle between the lower border of the 12th rib and the outer border of the erector spinae
Where can the kidney be palpated?
Can be palpated bimanually with one hand over the front and the other hand behind
When can the kidney be palpated?
When it is enlarged, it can be felt upon deep inspiration
