The posterior abdominal wall and Vasculature of abdomen.pdf

The document concentrate on the kidneys

1. Mrs. Sichela

2. The posterior abdominal region
is posterior to the abdominal part
of the gastrointestinal tract, the
spleen, and the pancreas
This area is bounded by bones
and muscles
Contains numerous structures that
not only are directly involved in
the activities of the abdominal
contents but also use this area as
a conduit between body regions.

3. Lumbar vertebrae and sacrum
Pelvic bones
oThe ilia, which are components of each
pelvic bone, attach laterally to the sacrum at
the sacro-iliac joints
oThe upper part of each ilium expands
outward into a thin wing-like area (the iliac
fossa).
oThe medial side of this region of each iliac
bone, and the related muscles, are
components of the posterior abdominal wall.
Ribs
oSuperiorly, ribs XI and XII complete the
bony framework of the posterior abdominal

4. Muscles forming the medial, lateral,
inferior, and superior boundaries of
the posterior abdominal region fill in
the bony framework of the posterior
abdominal wall
Mediallyare the psoas major and
minor muscles
Laterallyis the quadratus lumborum
muscle
Inferiorlyis the iliacusmuscle
Superiorlyis the diaphragm

5. Muscle Origin Insertion Innervation Function
Psoas major Lateral surface of bodies
of TXII and LI to LV
vertebrae, transverse
processes of the lumbar
vertebrae, and the
intervertebral discs
between TXII and LI to
LV vertebrae
Lesser trochanter of the
femur
Anterior rami of L1 to L3Flexion of thigh at hip
joint
Psoas minor Lateral surface of bodies
of TXII and LI vertebrae
and intervening
intervertebral disc
Pectineal line of the
pelvic brim and iliopubic
eminence
Anterior rami of L1Weak flexion of lumbar
vertebral column
Quadratus lumborum Transverse process of LV
vertebra, iliolumbar
ligament, and iliac crest
Transverse processes of
LI to LIV vertebrae and
inferior border of rib XII
Anterior rami of T12 and
L1 to L4
Depress and stabilize rib
XII and some lateral
bending of trunk
Iliacus Upper two-thirds of iliac
fossa, anterior sacroiliac
and iliolumbar ligaments,
and upper lateral surface
of sacrum
Lesser trochanter of
femur
Femoral nerve (L2 to L4)Flexion of thigh at hip
joint

6. The bean-shaped kidneys are
retroperitoneal in the posterior abdominal
region
They lie in the extraperitonealconnective
tissue immediately lateral to the vertebral
column.
In the supine position, the kidneys extend
from approximately vertebra TXII superiorly
to vertebra LIII inferiorly
The right kidney is somewhat lower than
the left because of its relationship with the
liver.
Although they are similar in size and shape,
the left kidney is longer and more slender
organ than the right kidney, and nearer to the
midline.

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9. Each kidney in the adult measures
about 11 to 12 cm in length, 6 cm
in breadth and 3 cm in
thickness.
Its weight ranges from 130 to 170g
On the upper pole of each
kidney is an adrenal gland.
The medial border of the kidney is
concave and contains a deep
vertical fissure, called the hilum
Renal vessels and nerves enter
kidney via hilum
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10. The pronephros, which forms in the cervical
región, is vestigial.
The mesonephros, which form in the thoracic and
lumbar regions, is large and is characterized by
excretory units (nephrons) and its own collecting
duct, the mesonephric or Wolffianduct.
In humans, it may function briefly, but most of the
system disappears.
Ducts and tubules from the mesonephrosform
the conduit for sperm from the testes to the
urethra.
In the female, these ducts regress.

11. The metanephros, or permanent
kidney, develops from two sources;
1.The ureteric bud gives rise to the
ureter, the renal pelvis, the major and
minor calyces, and approximately 1 to
3 million collecting tubules.
2.Metanephricmesoderm/blastema
form nephrons, or excretory units.
This ureteric bud is an outgrowth of the
mesonephric duct close to its entrance
to the cloaca

13. Unilateral renal agenesis: not very common. Males are affected more often than
females, and the left kidney is usually the one that is absent
Ectopic Kidneys: One or both kidneys may be in an abnormal position. Most
ectopic kidneys are located in the pelvis. Pelvic kidneys and other forms of ectopia
result from failure of the kidneys to alter position during embryo growth
Horseshoe Kidney: In 0.2% of the population, the poles of the kidneys are fused;
usually the inferior poles fuse.

14. Duplications of the Urinary Tract
These anomalies result from division of the metanephricdiverticulum (ureteric bud)
Duplications of the abdominal part of the ureter and the renal pelvis are common
The extent of the duplication depends on how complete the division of the diverticulum was.
Incomplete division of the metanephricdiverticulum results in a divided kidney with a bifid ureter
Complete division results in a double kidney with a bifid ureter or separate

15. Each kidney has two poles, two
surfaces and two borders
Hilum of Kidney
The hilum gives passage to the
renal vessels and the pelvis of the
ureter.
It is situated five cm away from the
midline.
The arrangement of the structures
at the hilum in anteroposterior
order is, renal vein, renal artery
and renal pelvis.
The hilum is continuous with an
internal space within each kidney
called the renal sinus.

16. Each kidney has four coverings. From
within outward, they are:
Renal/True capsule: tough fibrous
capsule.
Perinephric fat: collection of
extraperitonealfat.
Fascial capsule (false capsule, renal
fascia, or fascia of Gerota): encloses the
kidneys and the suprarenal glands.
oIts anterior layer is called fascia of
Toldt
oIts posterior layer is called fascia of
Zuckerkandl.
Paranephricfat: mainly located on the
posterolateral aspect of the kidney.

17. Each kidney consists of an outer renal cortex and an inner renal medulla.
The renal cortex is a continuous band of pale tissue that completely surrounds
the renal medulla.
Extensions of the renal cortex (the renal columns) project into the inner aspect
of the kidney, dividing the renal medulla into the renal pyramids
The bases of the renal pyramids are directed outward, toward the renal cortex,
while the apex of each renal pyramid projects inward, toward the renal sinus.
The apical projection (renal papilla) is surrounded by a minor calyx.
The minor calices receive urine and represent the proximal parts of the tube
that will eventually form the ureter
In the renal sinus, several minor calices unite to form a major calyx
Two or three major calices unite to form the renal pelvis, which is the
funnel-shaped superior end of the ureters.

21. The number of lobes in a kidney
equals the number of medullary
pyramids (8-12).
Each medullary pyramid and the
associated cortical tissue at its
base and sides constitutes a lobe
of the kidney.
The lobes of the kidney are
further subdivided into lobules
consisting of a central medullary
ray and surrounding cortical
material
Therefore, a lobule consists of a
collecting duct and all the
nephrons that it drains.
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22. The kidney contains about 1 million nephrons
This is the functional unit of the kidney
It consists of simple, single layered epithelium along their entire lengths.
They are two types of nephrons
Subcapsularnephrons or cortical nephrons are located almost completely in
the cortex, are the majority and have short loops of Henle
Juxtamedullarynephrons (about one-seventh of the total) lie close to the
medulla and have long loops of Henle.
The major divisions of each nephron are the following:
The renal corpuscle
The renal tubule
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24. Is responsible for the filtration
of plasma and is a combination
of two structures
Bowman’s capsule
distended blind end of the
renal tubule
The glomerulus
a globular network of
anastomosing capillaries
which invaginatesBowman’s
capsule
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25. The Bowman’s capsule is a double walled epithelial capsule
1. The internal or visceral (glomerular) layer of this capsule closely
envelops the glomerular capillaries which are fenestrated
2. The outer parietal layer forms the surface of the capsule.
Between the two capsular layers is the capsular(or urinary) space
It receives the fluid filtered through the capillary wall and visceral layer.
Each renal corpuscle has two poles
a vascular pole: where the afferent arteriole enters and the efferent
arteriole leaves
a tubular pole: where the proximal convoluted tubule (PCT) begins
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28. The renal tubule extends from Bowman’s capsule to its junction with
a collecting duct.
The renal tubule is up to 55mm long in humans and is lined by a
single layer of epithelial cells.
Functions
Reabsorptionof water, inorganic ions and other molecules from
the glomerular filtrate.
Secretion, some inorganic ions are secreted directly from blood
into the lumen of the tubule.
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29. Proximal convoluted tubule
Loop of Henle
Thick and thin
descending
Thick and thin ascending
Distal convoluted tubule
Connecting tubule
Collecting duct
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31. A single large renal artery, a lateral
branch of the abdominal aorta,
supplies each kidney
As each renal artery approaches the
renal hilum, it divides into anterior
and posterior branches, which
supply the renal parenchyma
Drainage is via the renal veins which
drain into the IVC
The lymphatic drainage of each
kidney is to the lateral aortic
(lumbar) nodesaround the origin of
the renal artery.

33. The ureters are muscular tubes that transport urine from the kidneys
to the bladder.
They are continuous superiorly with the renal pelvis, which is a
funnel-shaped structure in the renal sinus.
The renal pelvis narrows as it passes inferiorly through the hilum of
the kidney and becomes continuous with the ureter at the
ureteropelvicjunction
Inferior to this junction, the ureters descend retroperitoneallyon the
medial aspect of the psoas major muscle.
At the pelvic brim, the ureters cross either the end of the common
iliac or the beginning of the external iliac arteries, enter the pelvic
cavity, and continue their journey to the bladder.

34. At three points along their course the
ureters are constricted
the first point is at the ureteropelvic
junction;
the second point is where the ureters
cross the common iliac vessels at the
pelvic brim;
the third point is where the ureters
enter the wall of the bladder.
Kidney stones can become lodged at
these constrictions.

35. The ureters receive arterial branches
from adjacent vessels as they pass
towards the bladder:
Therenal arteries supply the upper
end
The middle part may receive branches
from the abdominal aorta, the
testicular or ovarian arteries, and the
common iliac arteries;
In the pelvic cavity, the ureters are
supplied by one or more arteries from
branches of the internal iliac arteries.

36. The suprarenal glands are associated with the superior pole of each
kidney
They consist of an outer cortex and an inner medulla.
The right gland is shaped like a pyramid, whereas the left gland is
semilunar in shape and the larger of the two.
The suprarenal glands are surrounded by the perinephric fat and
enclosed in the renal fascia, though a thin septum separates each gland
from its associated kidney.
Anterior to the right suprarenal gland is part of the right lobe of the liver
and the inferior vena cava, whereas anterior to the left suprarenal gland
is part of the stomach, pancreas, and, on occasion, the spleen.
Parts of the diaphragm are posterior to both glands

38. The arterial supply to the suprarenal
glands is extensive and arises from three
primary sources
as the bilateral inferior phrenic
arteries pass upward from the
abdominal aorta to the diaphragm, they
give off multiple branches (superior
suprarenal arteries) to the suprarenal
glands;
a middle branch (middle suprarenal
artery) to the suprarenal glands usually
arises directly from the abdominal
aorta;
inferior branches (inferior suprarenal
arteries) from the renal arteries pass
upward to the suprarenal glands.

39. The abdominal aorta begins at the aortic hiatus of the diaphragm as a
midline structure at approximately the lower level of vertebra TXII
It passes downward on the anterior surface of the bodies of vertebrae LI to
LIV,ending just to the left of midline at the lower level of vertebra LIV.
At this point, it divides into the right and left common iliac arteries.
This bifurcation can be visualized on the anterior abdominal wall as a point
approximately 2.5 cm below the umbilicus or even with a line extending
between the highest points of the iliac crest.
Branches of the abdominal aortacan be classified as:
Visceralbranchessupplying organs;
Posterior branches supplying the diaphragm or body wall; or
Terminal branches.

40. The visceral branches are either unpaired or paired vessels.
The three unpaired visceral branches that arise from the anterior surface of
the abdominal aorta are:
the celiac trunk, which supplies the abdominal foregut;
the superior mesenteric artery, which supplies the abdominal midgut; and
the inferior mesenteric artery, which supplies the abdominal hindgut.
The paired visceral branches of the abdominal aorta include:
the middle suprarenal arteries-small, lateral branches that supply the
suprarenal gland
the renal arteries-lateral branches of the abdominal aorta that supply the
kidneys
the testicularor ovarian arteries-anterior branches of the abdominal aorta

42. The posterior branches of the abdominal aorta are vessels supplying
the diaphragm or body wall.
They consist of the
Inferior phrenic arteries
The lumbar arteries
The median sacral artery

43. Artery Branch Origin Parts supplied
Celiac trunk Anterior Immediately inferior to the
aortic hiatus of the diaphragm
Abdominal foregut
Superior mesenteric arteryAnterior Immediately inferior to the
celiac trunk
Abdominal midgut
Inferior mesenteric arteryAnterior Inferior to the renal arteriesAbdominal hindgut
Middle suprarenal arteriesLateral Immediately superior to the
renal arteries
Suprarenal glands
Renal arteries Lateral Immediately inferior to the
superior mesenteric artery
Kidneys
Testicular or ovarian arteriesPaired anterior Inferior to the renal arteriesTestes in male and ovaries in
female
Inferior phrenic arteriesLateral Immediately inferior to the
aortic hiatus
Diaphragm
Lumbar arteries Posterior Usually four pairs Posterior abdominal wall and
spinal cord
Median sacral arteries Posterior Just superior to the aortic
bifurcation, pass inferiorly
across lumbar vertebrae,
sacrum, and coccyx
Common iliac arteries Terminal Bifurcation usually occurs at the
level of LIV vertebra

44. The inferior vena cava returns blood from all structures below the diaphragm to the right
atrium of the heart.
Itis formed when the two common iliac veins come together at the level of vertebra
LV, just to the right of midline.
It ascends through the posterior abdominal region anterior to the vertebral column
immediately to the right of the abdominal aorta, continues in a superior direction, and
leaves the abdomen by piercing the central tendon of the diaphragm at the level of
vertebra TVIII.
Tributaries to the inferior vena cava include the:
common iliac veins;
lumbar veins;
right testicular or ovarian vein;
renal veins;
right suprarenal vein;
inferior phrenic veins; and
hepatic veins

46. The lumbar plexus is formed by the anterior rami
of nerves L1 to L3, and most of the anterior ramus
of L4
It also receives a contribution from the T12
(subcostal) nerve.
Branches of the lumbar plexus include the
Iliohypogastric
Ilio-inguinal
Genitofemoral
Lateral cutaneous nerve of thigh (lateral
femoral cutaneous)
Femoral
Obturator nerves.
The lumbar plexus forms in the substance of the
psoas major muscle anterior to its attachment to
the transverse processes of the lumbar vertebrae

48. Branch Origin Spinal segments Function: motor Function: sensory
Iliohypogastric Anterior ramus L1 L1 Internal oblique and
transversus abdominis
Posterolateral gluteal skin
and skin in pubic region
Ilio-inguinal Anterior ramus L1 L1 Internal oblique and
transversus abdominis
Skin in the upper medial
thigh, and either the skin
over the root of the penis
and anterior scrotum or
the mons pubis and
labium majus
Genitofemoral Anterior rami L1 and L2L1, L2 Genital branch-male
cremasteric muscle
Genital branch-skin of
anterior scrotum or skin
of mons pubis and labium
majus; femoral branch-
skin of upper anterior
thigh
Lateral cutaneous nerve
of thigh
Anterior rami L2 and L3L2, L3 Skin on anterior and
lateral thigh to the knee
Obturator Anterior rami L2 to L4L2 to L4 Obturator externus,
pectineus, and muscles in
medial compartment of
thigh
Skin on medial aspect of
the thigh
Femoral Anterior rami L2 to L4L2 to L4 Iliacus, pectineus, and
muscles in anterior
compartment of thigh
Skin on anterior thigh and
medial surface of leg

55. The LI vertebral level is marked by the
transpyloricplane, which cuts transversely
through the body midway between the
jugular notch and pubic symphysis, and
through the ends of the ninth costal
cartilages.
At this level are:
the beginning and upper limit of the end of
the duodenum;
the hila of the kidneys;
the neck of the pancreas;
the origin of the superior mesenteric artery
from the aorta.
The left and right colic flexures are close to
this level

56. Each of the vertebral levels in the abdomen is related to the origin of major
blood vessels:
The celiac trunk originates from the aorta at the upper border of the LI
vertebra;
The superior mesenteric artery originates at the lower border of the LI
vertebra;
The renal arteries originate at approximately the LII vertebra;
The inferior mesenteric artery originates at the LIII vertebra;
The aorta bifurcatesinto the right and left common iliac arteries at the
level of the LIV vertebra;
The left and right common iliac veins jointo form the inferior vena cava
at the LV vertebral level.