Kidneys Location & Description
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Transcript of Kidneys Location & Description
Kidneys Location & Description
The waste products leave the kidneys as urine which passes down the
ureters to the urinary bladder which is located within the pelvis.
The urine leaves the body in the urethra. The kidneys are reddish
brown and lie behind the peritoneum high up on the posterior
abdominal wall on either side of the vertebral column. They are
largely under cover of the costal margin. The right kidney lies
slightly lower than the left kidney because the large size of the
right lobe of the liver. With contraction of the diaphragm during
respiration, both kidneys move downward in a vertical direction by
as much as 1 inch (2.5 cm ) . On the medial concave border of each
kidney is a vertical slit that is bounded by thick lips of the
renal substance and is called the hilum. The hilum extends into a
large cavity called the renal sinus. The hilum transmits from front
backward: The renal vein; two branches of the renal artery; ureter;
the 3rd branch of the renal artery ( V.A.U.A. ) ; lymph vessels and
sympathetic fibers . 1 2 3 &sinus Covering: Fibrous capsule: It
surrounds the kidney and is closely applied to its outer surface.
Perirenal fat: It covers the fibrous capsule. Renal fascia: It is a
condensation of connective tissue that lies outside the perirenal
fat and enclose the kidneys and suprarenal glands. It is continuous
laterally with the fascia transversalis. Pararenal fat: It lies
external to the renal fascia. It is in a large quantity. It forms
part of the retroperitoneal fat. N. B.2 & 3 and 4 support the
kidneys and hold them in position on the posterior abdominal wall.
Renal Structure Each kidney has a dark brown outer cortex and a
light brown inner medulla The medulla is composed of about a dozen
( 12 ) renal pyramids, each having its base oriented toward the
cortex and its apex ( renal papilla ) projecting medially. The
cortex extends into the medulla between adjacent pyramids as the
renal columns. Extending from the bases of the renal pyramids into
the cortex are striation(medullary rays ). The renal sinus is the
space within the hilum. It contains the upper expanded end of the
ureter ( renal pelvis ) which divided into 2 or 3 major calyces,
each of which divides into 2 or 3 minor calyces. Each minor calyx
is indented by the apex of the renal pyramid ( renal papilla).
Anterior Relations of the Right Kidney
The suprarenal gland; liver; second part of the duodenum; right
colic flexure and coils of small intestine. Anterior Relation of
the left Kidney The suprarenal gland; spleen; stomach; pancreas;
left colic flexure and coils of the jejunum. N.B. many of the
structures are directly in contact with the kidneys, whereas other
are separated by visceral layers of peritoneum. Posterior Relation
of the Right Kidney
The diaphragm; costodiaphragmatic recess of the pleura; 12th rib;
psoas; quadratus lumborum; transversus abdominis muscles; subcostal
(T 12 ); iliohypogastric and ilioinguinal nerves ( L1 ). Posterior
Relation of the Left Kidney As the right except that it lies higher
than the right. So, it is related to 11th and 12th ribs. N.B. the
right kidney lies at a slightly lower level than the left kidney
and the lower pole may be palpated in the right lumbar region at
the end of deep inspiration in a person with poorly developed
abdominal musculature. Arteries The renal artery arises from the
aorta at the level of the 2nd lumbar vertebra. Each renal artery
usually divides into 5 segmental arteries that enter the hilum of
the kidney, 4 in front and one behind the renal artery. Lobar
arteries arise from each segmental artery one for each renal
pyramid. Before entering the renal substance each lobar artery
gives off 2 or 3 interlobar arteries. The interlobar arteries run
toward the cortex on each side of the renal pyramid. At the
junction of the cortex and medulla, the interlobar arteries give
off the arcuate arteries which arch over the bases of the pyramids.
The arcuate arteries give off several interlobular arteries that
ascend in the cortex. The afferent glomerular arterioles arise as
branches of the interlobular arteries. Veins Clinical Notes Renal
Pain
The renal vein emerges from the hilum in front of the renal artery
and drains into the inferior vena cava. Lymph Drainage Lateral
aortic lymph nodes ( para- aortic ) around the origin of the renal
artery. Nerve Supply Renal sympathetic plexus. The afferent fibers
that travel through the renal plexus enter the spinal cord in the
10th ; 11th and 12th thoracic nerves. Clinical Notes Renal Pain It
varies from a dull ( not sharp ) ache to a severe pain in the flank
that may radiate downward into the lower abdomen. It can result
from stretching of the kidney capsule or spasm of the smooth muscle
in the renal pelvis. The afferent nerve fibers pass through the
renal plexus around the renal artery and ascend to the spinal cord
through the lowest splanchnic nerve in the thorax and the
sympathetic trunk. They enter the spinal cord at the level of T12 .
Pain is commonly referred along the distribution of the subcostal
nerve ( 12 ) to the flank and the anterior abdominal wall. Renal
Mobility The kidney are maintained in their normal position by
intra- abdominal pressure and by their connections with the
perirenal fat ; renal fascia and pararenal fat . Each kidney moves
slightly with respiration. If the amount of the perirenal fat be
reduced , the mobility of the kidney may become excessive and
produce symptoms of renal colic caused by kinking of the ureter.
Excessive mobility of the kidney leaves the suprarenal gland
undisturbed because both kidney and suprarenal are enclosed within
a separate compartment in the renal fascia. Also, any of them can
separate easily during operations. Kidney Trauma The kidney are
well protected by the lower ribs; lumbar muscles and vertebral
column. However, a severe blunt applied to abdomen may crush the
right kidney against the last rib & the left kidney against the
last 2 ribs and vertebral column. Because 25 % of the cardiac
outflow passes through the kidneys, renal injury can result in
rapid blood loss. The lower pole of the right kidney can be
palpated in the right lumbar region at the end of deep inspiration
in a person with poorly developed abdominal muscles. The normal
left kidney which is higher than the right is not palpable. Surface
Anatomy: On the anterior abdominal wall the hilum of each kidney
lies on the transpyloric plane, about 3 fingerbreadths from the
midline. On the back, the kidneys extend from the 12 thoracic spine
to the 3rd lumbar spine. The hili are opposite the spine of the 1st
lumbar vertebra. Draw oblique line, so that: Its upper end is 2.5
cm lateral to the median plane. Its center is 5 cm lateral to
median plane. Its lower end is 7.5 cm lateral to the median plane.
Ureter The 2 ureters are muscular tubes that extend from the
kidneys to the posterior surface of the urinary bladder. The urine
is propelled along the ureter by peristaltic contractions of the
muscle coat which are assisted by the filtration pressure of the
glomeruli. Each ureter measures about 10 inch ( 25 cm ) long. It
has 3 constrictions along its course: Where the renal pelvis joins
the ureter Where it is kinked as it crosses the pelvic brim. Where
it pierces the bladder wall. The renal pelvis is a funnel- shaped
expanded upper end of the ureter. It lies within the hilum of the
kidney and receives the major calyces Itemerges from the hilum of
the kidney and runs vertically downward behind the parietal
peritoneum which is adherent to it on the psoas muscle which
separates it from the tips of the transverse processes of the
lumbar vertebrae. It enters the pelvis by crossing the bifurcation
of the common iliac artery in front of the sacroiliac joint.
Posterior Relations of the Right Ureter
The ureter then runs down the lateral wall of the pelvis to the
region of the ischial spine and turns forward to enter the lateral
angle of the urinary bladder. Posterior Relations of the Right
Ureter Right psoas muscle which separates it from the lumbar
transverse processes. The bifurcation of the right common iliac
artery. Posterior Relations of the Left Ureter Left psoas muscle
and the bifurcation of the left common iliac artery. Anterior
Relation of the Right ureter
The 2nd part of the duodenum; terminal part of the ileum; right
colic and ileocolic vessels; right testicular or ovarian vessels
and the root of the mesentery of the small intestine. Anterior
Relation of the Left ureter The sigmoid colon; sigmoid mesocolon;
left colic vessels and the left testicular or ovarian vessels. N.B.
The inferior mesenteric vein lies along the medial side of the left
ureter. Arteries Veins Lymph Drainage Nerve Supply
The upper end is supplied by the renal artery The middle portion is
supplied by the testicular or ovarian artery. The pelvic part is
supplied by the superior vesical artery. Veins Venous blood drains
into the corresponding veins. Lymph Drainage The lymph drains into
the lateral aortic nodes and the iliac nodes. Nerve Supply Renal;
gonadal in the abdomen and hypogastric plexuses in the pelvis.
Afferent fibers travel with the sympathetic nerves and enter the
spinal cord in the 1st & 2nd lumbar segments Clinical Notes
Ureteric Stones Renal Colic
There are 3 sites of anatomic narrowing of the ureter where stones
may be arrested. Most stones, although radiopaque, are small enough
to be impossible to see definitely along the course of the ureter
on plane radiographic examination. An intravenous pyelogram is
usually necessary. The ureter runs down in front of the tips of the
transverse processes of the lumbar vertebrae, crosses the region of
the sacroiliac joint, swings out to the ischial spine and then
turns medially to the bladder. Renal Colic The renal pelvis and
ureter send their afferent nerves into the spinal cord at segments
T11 and 12 and L1 and 2. In renal colic, strong peristaltic waves
of contraction pass down the ureter in an attempt to pass the stone
onward. The spasm of the smooth muscle causes an agonizing colicky
pain which is referred to the skin areas that are supplied by these
segments of the spinal cord ( flank; loin and groin ). When a stone
enters the low part of the ureter, the pain is felt at a lower
level and is often referred to the testis or the tip of the penis
in the male and labium majus in the female. Sometimes ureteral pain
is referred along the femoral branch of the genitofemoral nerve (
L1 and 2 ) to the front of the thigh . The pain is often so severe
that afferent pain impulses spread within the central nervous
system giving rise to nausea. Suprarenal gland They are yellowish;
ductless and retroperitonealglands. They lie on the upper poles of
the kidneys. They are surrounded by renal fascia, but are separated
from the kidneys by the perirenal fat. Each gland has yellow cortex
and a dark brown medulla. The cortex of the glands secretes
hormones that include mineral corticoids which are concerned with
the control of fluid and electrolyte balance. Glucocorticoids which
are concerned with the control of the metabolism of carbohydrates;
fat; and proteins and small amounts of sex hormones which probably
play a role in the prepubertal development of the sex organs. The
medulla of the suprarenal glands secretes the catecholamines
epinephrine and norepinephrine. The right suprarenal gland:
It is pyramidal shaped and caps the upper pole of the right kidney.
It lies behind the right lobe of the liver and extends medially
behind the inferior vena cava. It rests posteriorly on the
diaphragm. The left suprarenal gland: It is crescentic in shape and
extends along the medial border of the left kidney from the upper
pole to the hilus. It lies behind the pancreas; lesser sac and
stomach and rests posteriorly on the diaphragm. Arteries Veins
Lymph Drainage Nerve Supply
They are inferior phrenic artery; aorta and renal artery. Veins A
single vein emerges from the hilum of each and drains into the
inferior vena cava on the right and into the renal vein on the
left. Lymph Drainage The lymph drains into the lateral ( para )
aortic nodes. Nerve Supply Preganglionic sympathetic fibers derived
from the splanchnic nerves supply the glands. Most of the nerves
end in the medulla of the gland.