Posterior abdominal wall Flashcards
Describe the Kidneys and the layers of facia covering it, from superficial to deep
-Primarily retroperitoneal
1) Paranephric (pararenal) fat
2) Renal fascia
- Prolonged inferiorly along ureters
- Helps prevent the spread of infection/blood locally, but acts as a conduit for the spread of these fluids into the pelvis
3) Perinephric (perirenal) fat
Describe kidney location
- At T12-L3 vertebral levels
- Right kidney typically lies slightly more inferior than left kidney
- Lie in the right or left upper quadrant
What are the outer borders of the kidney?
- Superior pole: adjacent to adrenal gland
- Inferior pole
- Lateral border is convex
- Medial border is concave and contains the renal hilum
Describe the Renal hilum
- Vertical cleft on medial border
- Arteries enter, veins and renal pelvis exit (VAP)
- Anterior: renal vein
- Middle: renal artery
- Posterior: renal pelvis
What are the layers surrounding the Kidneys?
- Renal capsule: is the very thin outer layer
- Renal cortex: is deep to the capsule
- Renal medulla: includes the renal pyramids and renal columns
Describe the pathway of the urine towards the ureter
Renal papillae –> 2-3 minor calyx –> 2-3 major calyx –> renal pelvis –> ureter
Describe the two cases of Anomalous kidneys
1) Pelvic kidney:
- Failure of kidney to ascend during development
2) Horseshoe kidney
- Right and left kidneys united at inferior poles
- Ascent stopped by IMA
Describe the Ureters
- Primarily retroperitoneal
- Fibromuscular tubes extending from renal pelvis to bladder
- Transport urine via peristaltic contractions
Describe the Adrenal (suprarenal) glands
- Primarily retroperitoneal
- Located on superomedial aspect of kidneys
- Enclosed by renal fascia
- Located in the right or left upper quadrant
Describe the Lymphatics of the Kidneys/Adrenal Glands
-Lymph drains to lumbar lymph nodes (along aorta) –> drains into chyle cistern thoracic duct
Describe Parasympathetic Innervation of the Kidneys
- Preganglionic cell bodies: brain
- Preganglionic fibers: vagus nn. (CN X)
- Postganglionic cell bodies and fibers: wall of kidney
Describe Sympathetic Innervation of the Kidneys
- Preganglionic cell bodies: lateral horn of the thoracolumbar spinal cord
- Preganglionic fibers travel from ventral root –> spinal nerve –> ventral ramus –> white ramus communicans –> sympathetic trunk –> thoracic splanchnic nn. (especially the least splanchnic n.)
- Postganglionic cell bodies: renal (aorticorenal) ganglion
- Postganglionic fibers: follow arterial branches to target organ
Describe Visceral pain from kidneys and ureters
- Follow the sympathetic pathway back to the spinal cord
- Refer to back, flank, groin, and genitals
Describe Sympathetic Innervation of the Adrenal Glands
- Preganglionic cell bodies: lateral horn of the thoracolumbar spinal cord
- Preganglionic fibers travel from ventral root –> spinal nerve –> ventral ramus –> white ramus communicans –> sympathetic trunk –> thoracic splanchnic nn. (greater, lesser, and least splanchnic nn.)
- Postganglionic cell bodies: secretory cells of adrenal medulla
What are the Vessels of the Posterior Abdominal Wall?
- Abdominal aorta
- Inferior Vena Cava (IVC)
Where does the Abdominal aorta start, run, and bifurcate?
- Begins at aortic hiatus of diaphragm (T12)
- Located to left of midline
- Bifurcates into common iliac arteries (L4)
What are the Unpaired branches of the abdominal aorta?
What do they supply blood to?
- Celiac trunk
- Superior mesenteric artery (SMA)
- Inferior mesenteric artery (IMA)
-Abdominal organs
What are the Paired branches of the abdominal aorta?
What do they supply blood to?
-Primarily retroperitoneal organs, gonads, and body wall
1) Inferior phrenic arteries:
- Supply inferior surface of diaphragm, adrenal glands (via superior suprarenal arteries)
2) Middle suprarenal arteries
3) Renal arteries:
- Right renal artery is longer than left and courses posterior to IVC
- Can have accessory renal arteries (failure of embryonic arteries to degenerate)
- Inferior suprarenal arteries
4) Gonadal (testicular or ovarian) arteries
5) Subcostal arteries
6) Lumbar arteries
What happens if an Abdominal aortic aneurysms ruptures?
-High mortality rates (~90%) if not diagnosed
Describe the Inferior Vena Cava (IVC)
-Formed by union of common iliac veins at L5 vertebral level
-Located to right of midline
-Exits abdomen through the caval opening (T8) of the diaphragm
-Tributaries of the IVC parallel the paired branches of the aorta
-Notable exceptions:
• Left gonadal vein drains to left renal vein
• Hepatic veins have no arterial complement
What are the Posterior Abdominal Wall Muscles?
1) Iliopsoas
a) Psoas major –> Origin: lumbar vertebrae
b) Iliacus –> Origin: iliac fossa
c) Psoas major fuses with iliacus to form iliopsoas, which inserts on the lesser trochanter of the femur
2) Quadratus lumborum –> Origin: 12th rib and lumbar vertebrae
- Insertion: iliac crest
What are the Nerves of the Posterior Abdominal Wall?
1) Subcostal nerves (ventral rami, T12)
2) Lumbar spinal nerves (ventral rami L1-L5) form the lumbar plexus
• Iliohypogastric & ilioinguinal nerves (L1)
• Genitofemoral nerve (L1, L2)
• Lateral cutaneous nerve of the thigh (L2-L3)
• Femoral nerve (L2-L4)
• Obturator nerve (L2-L4)
*Remember that ventral rami carry somatic motor, somatic sensory, and sympathetic fibers
3) Greater, lesser, least splanchnic nerves pass through diaphragm
4) Sympathetic trunks
Describe the Subcostal nerves (ventral rami*, T12)… where it passes, what it innervates, and what type of sensory it has.
- Travel laterally across quadratus lumborum
- Pierce transversus abdominis to enter abdominal wall
- Sensory innervation and sympathetic innervation to the T12 dermatome
- Motor innervation to external & internal obliques, transversus abdominis
Describe the Sympathetic trunks
- Continue from thorax
- Located just lateral to the lumbar vertebral bodies and along the anterior surface of the sacrum
