Posterior Abdominal Wall Flashcards
Muscles of posterior abdominal wall
Psoas major and minor
Iliacus
Quadratus lumborum
diaphragm
Origin of psoas major and minor mm.
Transverse processes and sides of vertebral bodies and intervertebral disks of T12-L5
Insertion of psoas major and minor mm.
Tendon to the lesser trochanter of femur
Innervation of psoas major and minor mm.
Anterior rami of L1-3
Origin of iliacus m.
Superior 2/3 iliac fossa, ala, anterior sacroiliac ligaments
Insertion of iliacus m.
Lesser trochanter and shaft below
Innervation of iliacus m.
Femoral n (L2-4)
Origin of quadratus lumborum m.
Medial 1/2 of inferior surface of 12th rib + tips of lumbar transverse processes
Insertion of quadratus lumborum m.
Iliolumbar ligament and lip of iliac crest
Innervation of quadratus lumborum m.
Anterior T12, L1-L4
Origin/insertion/innervation of psoas major and minor mm.
Origin: transverse processes and sides of vertebral bodies and intervertebral disks of T12-L5
Insertion: tendon to the lesser trochanter of femur
Innervation: anterior rami of L1-3
Origin/insertion/innervation of iliacus m.
Origin: superior 2/3 iliac fossa, ala, anterior sacroiliac ligaments
Insertion: lesser trochanter and shaft below
Innervation: femoral n. (L2-4)
Origin/insertion/innervation of quadratus lumborum m.
Origin: medial 1/2 of inferior surface of 12th rib + tips of lumbar TPs
Insertion: iliolumbar ligament and lip of iliac crest
Innervation: anterior T12, L1-4
A patient presents with flank pain and a fever. On PE you note that they are limping and they have a palpable inguinal mass. You perform a special test in which you have them extend their thigh, which exacerbates the pain. What is your likely diagnosis?
Psoas abscess (+ psoas sign)
What are some causes of psoas abscess?
Disease of organs (e.g., TB spread to abdomen), cancer such as adenocarcinoma, and infections deep to psoas fascia
What ligament forms the tendinous arch of the crura of the diaphragm, uniting right and left crura?
Median arcuate ligament
What ligament forms as a fascial thickening of the psoas fascia, spanning lumbar body and tip of L1 transverse process?
Medial arcuate ligament
How does medial arcuate ligament relate to median arcuate ligament?
Medial is lateral to median
What ligament forms as fascial thickening of quadratus lumborum m. Running from L1 TP to the tip of 12th rib?
Lateral arcuate ligament
Where in the diaphragm would you find the caval opening?
Central tendon
What are the 7 paired arteries of the posterior abdominal wall?
Subcostal aa. Inferior phrenic aa. Suprarenal aa. Renal aa. (L2) Gonadal aa. (L2) Lumbar aa. Deep circumflex iliac aa.
What are the 4 unpaired arteries of the posterior abdominal wall?
Celiac trunk (T12)
Superior mesenteric a. (L1)
Inferior mesenteric a. (L3)
Medial sacral a.
The IVC begins anterior to vertebral level ____ and right of medial plane; it passes through the ____ hiatus of the diaphragm
L5; caval
The tributaries of the IVC are corresponding veins of paired visceral and parietal branches of aorta.
What are the paired visceral branches?
Suprarenal v.
Renal v.
Gonadal v.
The tributaries of the IVC are corresponding veins of paired visceral and parietal branches of aorta.
What are the paired parietal branches?
Inferior phrenic v.
3rd and 4th lumbar v.
Common iliac v.
The ______ vein and ____ vein connect the SVC and IVC, either directly or indirectly
Ascending lumbar; azygous
The caval opening in the diaphragm is at approximately vertebral level _____.
What 2 things pass through the caval opening?
T8
IVC and right phrenic n.
The esophageal hiatus of the diaphragm is at vertebral level _____.
What 2 things pass through the esophageal hiatus?
T10
Esophagus
Anterior/posterior vagal trunks
The aortic hiatus of the diaphragm is at vertebral level _____.
What 2-4 things pass through the aortic hiatus?
Aorta
Thoracic duct
Sometimes azygous and hemiazygous vv.
What are the 2 parts of the muscular diaphragm? What do they attach to?
Sternal part - attaches to xiphoid
Costal part - attaches to inferior 6 costal cartilages
Describe crura of muscular diaphragm
Right crus = larger and longer (L3-L4 vertebral bodies); some fibers run along left side of aortic hiatus
Left crus = (L2-L3 vertebral bodies)
note that esophageal hiatus is typically surrounded by right crural fibers, even though it may be slightly to the left
What arteries supply the superior side of the diaphragm?
Superior phrenic a. (off internal thoracic a.)
Musculophrenic and pericardiacophrenic a. (Off thoracic aorta)
What arteries supply the inferior side of the diaphragm?
Inferior phrenic a. (Off abdominal aorta)
Intercostal branches for peripheral diaphragm
What type of hernia occurs due to weakening of the muscular diaphragm?
Hiatal hernia
What are the 2 types of hiatal hernia?
Para-esophageal: pouch of peritoneum and stomach fundus extend through esophageal hiatus usually anterior to esophagus. Gastric regurg usually does not occur and cardia portion is normal.
Sliding hiatal hernia: abdominal esophagus, cardia, and portion of fundus extends through esophageal hiatus. Regurgitation of stomach contents is possible.
Kidneys are primarily retroperitoneal, lying at ____ to ____ vertebral levels.
The ____ kidney sits lower in the abdominal cavity. The renal ____ is the entrance to the renal sinus.
T12-L3
Right; hilum
How do the kidneys relate to the transpyloric plane?
The left kidney hilum is near the transpyloric plane (about 5 cm from median plane)
The transpyloric plane runs through the superior pole of the right kidney (2.5 cm lower than left)
From a posterior approach, the superior parts of the kidneys lie deep to what bony structures?
11th and 12th ribs
What anatomical landmark is used to approximate the location of the inferior pole of the right kidney?
Right kidney is approximately index fingers breadth superior to iliac crest
The posterior approach, particularly regarding the right kidney, means encountering what muscle lying posterior to the largest part of the kidney (with intervening fat)?
Quadratus lumborum m.
When surgically accessing a kidney, the posterior approach is often used to avoid entering the peritoneum where there is a higher risk of infection. While the posterior approach is better for this reason, it does require going through the quadratus lumborum m. as well as the nerves that sit between the muscle and the fat overlying the kidney.
What are these nerves?
Subcostal nn. (typically protected by 12th rib)
Iliohypogastric (L1)
Ilioinguinal (L1)
_______ fat = adjacent kidney capsule that extends into renal pelvis
______ fat = external to renal fascia
Perinephric
Paranephric
Describe renal fascia
Covers the fat enveloping the kidney and suprarenal gland (perinephric fat); blends and ensheaths renal vessels
Superiorly continuous with inferior diaphragmatic fascia
What is normal renal mobility in the abdominal cavity?
~3 cm
Describe location of ureters in the abdominal cavity
Run inferiorly from renal pelvis passing over pelvic brim and along lateral pelvic wall and posterior to ductus deferens (male) and uterine artery (female)
What are the 3 major constriction points of the ureter (aka potential sites of obstruction with things like kidney stones)
Junction of ureter with renal pelvis
Crossing pelvic brim
Entering bladder wall
______ = x-ray of ureter enhanced with contrast
Pyelogram
What are the first branches off the renal arteries supplying the inner kidney?
Segmental aa.
The ureters pick up arterial supply from multiple sources as they travel down the abdominal cavity. What are some of these sources?
Renal branches Gonadal branches Abdominal aorta branches Iliac branches Superior vesicular branches Pelvic branches - rectal, uterine, vaginal, inferior vesicular
What are some anatomical landmarks near the right suprarenal gland?
Right crus of diaphragm
Right kidney
IVC
What are some anatomical landmarks near the left suprarenal gland?
Left crus of diaphragm
Spleen
Stomach
Pancreas
3 major sources of arterial supply of suprarenal glands
Superior suprarenal a.
Middle suprarenal a.
Inferior suprarenal a.
[superior and middle suprarenal aa. come from aorta, inferior suprarenal a. comes from renal a.]
Innervation of suprarenal glands
Preganglionic sympathetic for T10-11
Celiac plexus and splanchnic nn.
Trace lymphatic flow from external/internal iliac nodes in posterior abdominal wall
External/internal iliac nodes —> common iliac nodes —> lumbar nodes/trunks (also receiving from posterior wall and posterior pelvic wall and organs) —> pre-aortic nodes —> cisterna chyli —> thoracic duct
Which lymph nodes associated with the posterior abdominal wall run along both sides of the IVC and aorta and receive from the posterior wall and posterior pelvic wall and organs?
Lumbar lymph nodes
Which lymph nodes associated with the posterior abdominal wall form intestinal lymphatic trunks draining from alimentary tract, liver, spleen, and pancreas?
Pre-aortic lymph nodes
List the nerves associated with the posterior abdominal wall
Subcostal n Iliohypogastric n Ilioinguinal n Genitofemoral n Lateral femoral cutaneous n Femoral n Obturator n Lumbosacral trunk
What nerve associated with the posterior abdominal wall would you find on the surface of the psoas m.?
Genitofemoral n.
Removal of the psoas muscle would reveal what group of nerves associated with the posterior abdominal wall?
Lumbar plexus
6 branches/roots of lumbar plexus
Iliohypogastric (L1) Ilioinguinal (L1) Genitofemoral (L1, L2) Lateral cutaneous nerve of thigh (L2, L3) Obturator (L2-L4) Femoral (L2-4)
The iliohypogastric branch of the lumbar plexus originates from anterior ramus of L1. What are its motor vs. sensory functions?
Motor: internal oblique and transversus abdominis
Sensory: posterolateral gluteal skin and skin in pubic region
The ilioinguinal branch of the lumbar plexus originates from anterior ramus of L1. What are its motor vs. sensory functions?
Motor: internal oblique and transversus abdominis
Sensory: 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
The genitofemoral branch of the lumbar plexus originates from anterior ramus of L1 and L2. What are its motor vs. sensory functions?
Motor: genital branch = male cremasteric m.
Sensory: genital branch = skin of anterior scrotum or skin of mons pubis and labium majus; femoral branch = skin of upper anterior thigh
The lateral cutanous nerve of the thigh - branch of the lumbar plexus - originates from anterior ramus of L2 and L3. What are its sensory functions?
Skin on anterior and lateral thigh to the knee
The obturator branch of the lumbar plexus originates from anterior ramus of L2 to L4. What are its motor vs. sensory functions?
Motor: Obturator externus, pectineus, and muscles in medial compartment of the thigh
Sensory: skin on medial aspect of the thigh
The femoral branch of the lumbar plexus originates from anterior ramus of L2 to L4. What are its motor vs. sensory functions?
Motor: iliacus, pectineus, and muscles in anterior compartment of thigh
Sensory: skin on anterior thigh and medial surface of leg
