Download Region 16: Kidneys and Retroperitoneal Structures Abdominal aorta

Region 16: Kidneys and Retroperitoneal Structures
Abdominal aorta
--appears in abdomen at aortic hiatus of diaphragm at T12 vertebrae
--ends in front of L4 by dividing into left and right common iliac arteries
--Unpaired branches from its anterior surface
*unpaired celiac trunk
*unpaired superior mesenteric artery
*unpaired inferior mesenteric artery
--paired branches from its lateral side
--unpaired branch from dorsolateral side
*unpaired median sacral artery
Renal Fascia
--anterior and posterior lamellae fuse lateral, superior, and medial to kidneys
*separate extraperitoneal fat into perirenal fat (adjacent to kidneys) and
pararenal fat (behind posterior lamella of renal fascia
Suprarenal Glands
--located at superior medial aspect of kidneys
--since cortical part of suprarenal glands produce steroids, gland appears fatty and
may pass for some of fat that surrounds kidney
--Blood supply to suprarenal glands
*three sets of aa. supply the glands
a. superior suprarenal aa: branch from inferior phrenic aa.
b. middle suprarenal aa.: brach directly off aorta
c. inferior suprarenal aa: branches of renal aa.
*one major suprarenal vein drains suprarenal gland
a. right side: vein drains directly into inferior vena cava
b. left side: vein usually joined by inferior phrenic vein before
emptying into left renal vein
--suprarenal medulla: innervated directly by preganglionic sympathetic fibers
Kidneys
--external features
*medial border is indented by a hilum
--internal anatomy
a. hilus opens into renal sinus contains renal vessels, nerve, lymphathics,
major and minor calyces, and renal pelvis (enlarged upper end of ureter)
b. medulla: characterized by pyramids whose apexes project into minor calyx
as a papilla and its base lies at corticomedullary junction
c. pyramids are separated by cortical tissue designated as renal columns
(some of the collecting ducts of the pyramids continue into cortex  called
medullary rays)
--Blood Supply
*renal arteries: branch from aorta at level of L1
a. right renal a.: passes posterior to inferior vena cava
--divides as it approaches the kidney to form segmental aa.
--inferior suprarenal aa: branches of renal aa.
*renal veins: tributaries of inferior vena cava
a. left renal vein: passes in front of aorta immediately below origin of
superior mesenteric a.
Ureters
--Minor calyces: join to form major calyces, which form the renal pelvis (upper
expanded part of ureter)
--relationships of the ureter
*through most of their course, the ureters lie on the psoas muscles, then
cross the bifurcation of the common iliac vessels to enter the pelvis
Inferior Vena Cava
--begins at elvel of L5 by confluence of the left and right common iliac vein
--ends at level of T8 where it passes through the diaphragm
--lies to the right of the aorta
--has tributaries
--important collateral routes b/w superior and inferior vena cava include
*thoracoepigastric veins
*ascending lumbar veins: change to azygos vein on right and hemiazygos on
left
Lymphatics
--Cisterna Chyli
*lies on bodies of L1 and L2
*dilated sac that receives lymph gathered from lower part of the body
*it is the inferior end of the thoracic duct
--Thoracic Duct
*leaves the abdomen by way of the aortic hiatus and travels b/w the aorta
and azygos vein
Autonomic Nervous system of the Abdomen
--while the chain ganglia of the sympathetic system are well defined anatomically,
the collateral ganglia on the vental side of the aorta are not
--Sympathetic system
*white communicating ramus (L1-2)
*postganglionic fibers enter the gray communicating rami to follow spinal
nerves of the lumbar plexus
--collateral ganglia
*preganglionic fibers enter them via the thoracic splanchnice nerves (greater,
lesser, least) and the lumbar splanchnic nerves
*celiac ganglion: receives preganglionic fibers from the thoracic splanchnic
nerves
*ganglion impar/coccygeal ganglion: terminal convergence of sympathetic
trunks, anterior to coccyx and single
--Parasympathetic System
a. preganglionic parasympathetic supply to the structures derived from
foregut (stomach, duodenum, liver, gallbladder, pancreas) and midgut
(jejunum, ileum, ascending and transverse colons) via the vagus nerves
b. preganglionic parasympathetic fibers to the hindgut structures
(descending and sigmoid colon, rectum) and the pelvic organs arise in
segments S2,3,4 of the spinal cord
c. fibers enter pelvis plexus via pelvic splanchnic nerve (parasympathetic)
d. nervus erigentes
*preganglionic parasympathetic fibers of the pelvic splanchnic nerves
going to terminal pelvic ganglia