Transcript 31-Aorta& IVC

Aorta
The aorta enters the abdomen through the
aortic opening of the diaphragm in front of
the 12th thoracic. It descends behind the
peritoneum on the anterior surface of the
bodies of the lumbar vertebrae.
At the level of the 4th lumbar vertebra, it
divides into the 2 common iliac arteries.
On its right side lie the inferior vena cava the
cisterna chyli and the beginning of the
azygos vein.
On its left side lies the sympathetic trunk
Branches
3 ( single ) anterior visceral branches:
celiac; superior and inferior mesenteric.
3 ( paired ) lateral visceral branches:
suprarenal; renal and gonadal.
5 ( paired ) lateral abdominal wall branches:
inferior phrenic and 4 lumbar arteries.
3 ( single ) terminal branches:
2 common iliac and the median sacral
arteries
Inferior Phrenic Arteries
They arises from the aorta above the celiac trunk. It gives
rise to 2 or 3 suprarenal arteries and diaphragmatic
branches to diaphragm.
Middle Suprarenal arteries
They arises from the side of the aorta at the level of the
superior mesenteric artery ( L1 ).
Renal arteries
They arises from the side of the aorta just below the
superior mesenteric artery opposite L2 vertebra. It gives
rise to inferior suprarenal artery; ureteric artery to the
upper part of the ureter and terminal branches to the
kidney.
Lumbar Arteries
They are 5 ( pairs ) on each side. The upper 4 arise from the
aorta and the 5th pair arise from the median sacral.
They give rise to radicular arteries which pass through the
intervertebral foramina into the vertebral canal to supply
the menings of the spinal cord. Also, they supply the
muscles of the posterior and anterior abdominal wall.
Testicular Arteries
They arise from the aorta a little below the
origin of the renal arteries. Both right & left
arteries cross superficial to the ureter and
genitofemoral nerve and then the right one
passes deep to the ileum while the left one
passes deep to the colon.
They join the spermatic cord at the deep
inguinal ring and traverses the inguinal canal.
Each artery leaves the inguinal canal through
the superficial inguinal ring and descends to
the scrotum.
At the upper pole of the testis, it breaks into
branches which supply the testis and
epididymis.
Ovarian arteries
They descend like the testicular arteries till the
pelvic brim where they turn medially and
cross the front of the external iliac artery and
enter the suspensory ligament of the ovary.
They supply the ureter; ovary; uterus and
uterine tubes.
Median Sacral Artery
It arise from the back of the aorta just
above its bifurcation.
It descends in the midline behind the
rectum in front of the 4th and 5th
lumbar vertebrae; sacrum and
coccyx to end in the anococcygeal
body.
It gives rise to the 5th pair of lumbar
arteries; rectal branch to the back of
the rectum and small branches that
pass through the anterior sacral
foramina to supply the contents of
the sacral canal.
Common iliac arteries
They are the terminal branches of
the aorta. They arise at the level of
the 4th lumbar vertebra and run
downward and laterally along the
medial border of the psoas major
muscle.
Each artery ends in front of the
sacroiliac joint by dividing into the
external and internal iliac arteries.
It is crossed at its bifurcation by
the ureter.
Internal iliac artery
It passes down into the pelvis in
front of the sacroiliac joint.
External Iliac Artery
It runs along the medial border of the psoas following the pelvic brim. It gives off
inferior epigastric and deep circumflex iliac arteries. It passes under the inguinal
ligament to enter the thigh and become the femoral artery.
The inferior epigastric artery arises just above the inguinal ligament. It passes
upward and medially along the medial margin of the deep inguinal ring and enters
the rectus sheath behind the rectus abdominis muscle.
The deep circumflex iliac artery arises close to the inferior epigastric artery. It
ascends laterally to the anterior superior iliac spine and iliac crest supplying the
muscles of the anterior abdominal wall.
Surface Anatomy of Aorta
Point 1 in the median plane one inch above the transpyloric plane.
Point 2 lies half inch below and to the left of the umbilicus ( at the level of the supracristal
plane) which connects the highest parts of the 2 iliac crests.
Connect point 1 by 2 vertical lines 2 cm apart.
Inferior Vena Cava
It is formed by the union of the common iliac artery at the level of the 5th lumbar vertebra.
So, it conveys most of the blood from the body below the diaphragm and drains into the
right atrium of the heart.
It ascends on the right side of the aorta. It pierces the central tendon of the diaphragm at the
level of the 8th thoracic vertebra.
The right sympathetic trunk lies behind its right margin and the right ureter lies 0. 5 inch
from its right border.
The entrance into the lesser sac ( epiploic foramen ) separates the inferior vena cava from
the portal vein.
Tributaries
1. 2 anterior visceral tributaries:
The hepatic veins.
2. 3 lateral visceral tributaries:
The right suprarenal vein; renal veins; right gonadal
vein.
3. 5 lateral abdominal wall tributaries:
The inferior phrenic vein and 4 lumbar veins.
4. 3 Veins of origin: 2 common iliac veins and the median
sacral vein.
N.B.
1. The left suprarenal vein drains into the left renal vein.
2. The left gonadal vein drain into the left renal vein which
is 7.5 cm long.
3. The right renal vein is 2.5 cm.
4. The 5th lumbar vein drains in iliolumbar vein.
5. The ascending lumbar vein is long channel which
begins at the lateral sacral veins and ends in the azygos
vein on the right side and in the inferior hemiazygos
vein on the left side.
Superior Mesenteric Vein
It begins at the ileocecal junction.
It runs upward on the posterior
abdominal wall within the root of
the mesentery on the right side of
the superior mesenteric artery.
It passes in front of the 3rd part of
the duodenum and behind the
neck of the pancreas where it
joins the splenic vein to form the
portal vein.
It receives tributaries that
correspond to the branches of the
superior mesenteric artery.
Also, receives the inferior
pancreaticoduodenal vein and the
right gastroepiploic vein.
Splenic Vein
It begins at the hilum of the spleen by
the union of several veins, then it is
joined by the short gastric and the left
gastroepiploic veins.
It passes to the right within the
splenicorenal ligament and runs behind
the body of the pancreas below the
splenic artery.
It joins the superior mesenteric vein
behind the neck of the pancreas to form
the portal vein.
It is joined by veins from the pancreas
and inferior mesenteric vein.
Inferior Mesenteric Vein
It begins halfway down the anal
canal as the superior rectal vein.
It passes up the posterior
abdominal wall on the left side of
the inferior mesenteric artery and
the duodenojejunal flexure.
It joins the splenic vein behind the
pancreas.
It receives tributaries that
correspond to the branches of the
artery.
Surface Anatomy of I.V.C.
Point 1 lies on the transtubercular plane, 2.5 cm to the right of the median plane.
Point 2 on the sternal end of the right 6 costal cartilage.
Connect point 1 by 2 vertical lines 2.5 cm apart.
Caval Obstruction
If the superior or inferior vena
cava is obstructed, the venous
blood causes distension of the
veins running from the anterior
chest wall to the thigh.
The lateral thoracic vein
anastomoses with the superficial
epigastric vein ( tributary of the
great saphenous vein of the leg ).
In these circumstances, a
tortuous varicose vein may
extend from the axilla to the lower
abdomen.