Posterior abdominal wall Like a boss

Psoas major

Psoas minor Arise from T 12 to L 1-5, intervertebral discs, transverse processes lumbar vert Passes inferiorly along pelvic brim to anterior thigh, under inguinal ligament Attaches to lesser trochanter of femur Minor sometimes absent

Iliacus

Quadratus lumborum Ribs 7 to iliac crest

Attachment for lateral arcuate ligament

Top Left: Axial CT Top Right: Sagittal CT BL: Ant. Abdomen BR: Lateral Chest

Right crus L1 – L3

Left crus L1 – L2

Median, medial, lateral arcuate ligaments

Hiatuses: caval, aortic, esophogeal

Aortic hiatus

Sweet

Esophogeal hiatus

Kidney; a retroperitoneal Organ

Perinephric (perirenal) fat and paranephric (pararenal) fat Must incise renal fascia to reach organ in procedures

Pararenal fat

Renal cortex and cortical columns

Renal medulla

Renal sinus

Renal papilla

Minor calyx

Major Calyx

Renal pelvis

Renal ureter Drainage of urine from kidneys to bladder 3 constriction points: ureteropelvic junction, ureter intersection with iliac vessels at pelvic brim, entrance point for ureters into bladder Kidney stones can be lodged in these constrictions

Middle suprarenal artery

Renal artery

Inferior suprarenal artery

Lumbar arteries Usually 4 branches Arise from posterior abdominal aorta

Common iliac arteries

Median sacral artery Arises from posterior surface of abdominal aorta

Testicular arteries

Ovarian Arteries

Renal veins Left renal vein longer and cross midline in front of abdominal aorta Crosses behind superior mesenteric artery Can be compressed by aneurysm in these two vessels

Suprarenal veins Right suprarenal- short, passes directly into IVC Left suprarenal- passes inferiorly to renal vein

Ovarian/testicular veins

Inferior phrenic veins

Right subcostal vein

Ascending lumbar vein Receives drainage from first and second lumbar veins Connect common iliac, iliolumbar, lumbar veins with azygos, hemiazygos veins of thorax Serves as important collateral channels between lower and upper parts of body if IVC becomes blocked

Intermesenteric plexus

Phrenic nerve

Subcostal nerve

Subcostal nerve

Iliohypogastric nerve Arises from L1 along with ilio-linguinal Laterla to psoas major

Iliohypogastric nerve

Ilio-inguinal Arises from L1 Smaller, inferior to iliohypogastric

Genitofemoral nerve (genital branch- medial) (femoral branch- lateral) Arises from anterior L1/2 Genital branch continues downward and enters inguinal canal through deep inguinal ring Femoral branch enters femoral sheath, lateral to femoral artery

Obturator nerve Anterior L2-4 Enters obturator canal

Lateral cutaneous nerve of thigh Arises from L2-L3 Supplies skin of anterior and lateral thigh to level of knee

Lumbosacral trunk Meeting of lumbar plexus and sacral plexus

Cisterna Chyli Trunks from lumbar nodes and lumbar trunks form cisterna chyli Lies to the right side of abdominal aorta at L1/2 Marks the beginning of thoracic duct

Lateral aortic (lumbar) nodes Receive from body wall, kidneys (upper ureter), suprarenal glands, and testes/ovaries (Middle portion ureters) common iliac nodes (inferior portion ureters) external and internal iliac vessels

Thoracic duct Recieves drainage from posterior abdominal region

Vertebrocostal trigone

QUIZ

1. Posas minor

2. Major calyx

3. Lumbar arteries

4. Identify the structure. What nerve arises from the lateral bifurcation of this main nerve? What nerve arises from the medial bifurcation of this main nerve?

5. All of the following drain into the the lateral aortic (lumbar) lymph nodes EXCEPT: Body wall of posterior abdominal region Upper portion of kidney ureters Suprarenal glands Spleen Testes/ovaries D- the spleen drains into its corresponding mesenteric node (celiac, superior or inferior mesenteric node)

6. Identify the structure (be specific). At which vertebral level does it penetrate the diaphragm? Abdominal aorta T12

7. Identify the structure. What does it mark the beginning of? Cisterna chyli Thoracic duct

Ate. Why is the Psoas major muscle sheath of greater importance than ANY OTHER muscle sheath? Muscle and sheath arise from both the lumbar vertebrae BUT ALSO the intervertebral discs; therefore, if infection (i.e. tuberculosis and Salmonella discitis) occurs and spread  anterior and anterolateral into psoas major sheath  may appear below inguinal ligament as a MASS!