Posterior Abdominal Wall Flashcards
The posterior abdominal wall acts as a conduit for what structures?What structures are found on the posterior abdominal wall?
- conduit
- abdominal aorta (and nerve plexuses)
- inferior vena cava
- sympathetic trunk
- lympatics
- lumbar plexus
- kidneys
- adrenal glands
Identify the bony landmarks associated with the posterior abdominal wall
Identify the muscule indicated in the image
Origin?
Insertion?
Nerve supply?
Actions?
What sister muscle is sometimes present?
origin?
insertion?
nerve supply?
Psoas major
- Origin
- bodies T12 and L1-5
- intervertebral bodies
- transverse processes L1-5
- Insertion
- lesser trochanter of femur (under inguinal ligament)
- Nerve supply
- ventral rami L1-3
- Actions
- bilateall: flexes trunk from supine position (with thighs fixed)
- unilaterally: lateral flexion of trunk
Psoas minor (sister muscle– not always present)
- origin
- vertebrae T12 and L1
- intervertebral discs
- insertion
- pectineal line
- iliopubic eminence
- nerve supply
- ventral rami L1
What muscle is indicated in the photo provided?
origin?
insertion?
nerve supply?
action?
Quadratus lumborum
- origin
- transverse process L5
- iliolumbar ligament
- adjoinign iliac crest
- insertion
- transverse process L1-L4
- inferio boder rib 12
- nerve supply
- ventral rami T12; L1-4
- action
- unilateral
- depress/stabilize rib 12
- lateral flexion trunk
- bilateral
- extension lumbar vertebral column (?)
- unilateral
Attachment points for iliolumbar ligament?
iliac crest to L5
What muscle is indicated in the provided image?
origin?
insertion?
nerve supply?
action?
Iliacus – lateral to inferior psoas muscle
- origin
- superior 2/3rd of iliac fossa
- ala of sacrum
- anterior sacroiliac ligaments
- insertion
- lesser trochanter w/ psoas major tendon
- nerve supply
- femoral nerve (from lumbar plexus L2-4)
- action
- flexes the thigh
- has NO action on lumbar vertebral column
What muscles is shown in the provided image
This muscle is composed of what 2 parts?
Boundary?
Insertion & associated ligaments?
Blood supply?
Innervation?
- Diaphragm
- central tendinous part + circumferential muscle fibers
- dividing line between the thorax and abdomen
- anchored to lumbar vertebrae via crura
- right crus: L1-3 – split to form esophageal hiatus
- left crus: L1-2
- medial arcuate ligament – between the 2 crura
- medial arcuate ligament – between body and transverse process L1 (passage psoas major)
- lateral arcuate ligament– rip rib 12 to transverse process L1 (passage quadratus lumborum)
- Blood supply
- superiorly
- superior phrenic artery
- musculophrenic and pericardiophrenic artery
- inferiorly
- inferior phrenic artery
- superiorly
- Innervation
- motor:
- phrenic nerve (ventral rami C3-5)
- sensory:
- phrenic nerve
- peripherally T5-11 and T12
- motor:
What are the 3 apetures in the diaphragm? What passes through each and at what vertebral level do they occur?
- caval foramen (T8)
- IVC
- terminal branch of right phrenic nerve
- lymphatics
- esohpageal hiatus (T10)
- esophagus
- anterior and posterior vagal trunks
- lymphatics
- esophageal branch of L. gastric artery
- aortic hiatus (T12)
- descendign aorta
- thoracic duct
- +/- azygous and hemi-azygous v.
What is Kehr’s sign?
acute pain int eh tip of the left shoulder due to diaphragmatic irritation
It is signaled by phrenic nerve (C3-5); the supraclavicular nerve also originates from C3-4, which is why diaphragmatic disruption (or pericardium, pleura or spleen) can be interpreted as soulder pain
What are the layers of fascia in the posterior abdominal wall?
- transverasalis fascia
- external to parietal peritoneum
- lines internal abdominal wall & inferior diaphragm
- Thoracolumbar fascia (tri-laminar)
- anterior (surrounds/invests posterior abdominal wall muscles)
- Quadratus lumborum fascia
- Psoas fascia
- Iliacus fascia
- anterior (surrounds/invests posterior abdominal wall muscles)
Where does the abdominal aorta start?
identify the branches indicated in the provided image
begins at aortic hiatus (~T12) after passing behind median arcuate ligament
bifurcation at L4
Visceral
- unpaired - 3 branches
- celiac trunk (T12)
- Superior mesenteric (L1)
- Inferior mesenteric (L3)
- Paired – 3 branches
- middle suprarenal (L1)
- renal (betweel L1 and L2) –> hilum
- Gonadal (testicular or ovarian) (L2)
Posterio or Parietal Branches
- inferior phrenic
- adrenals and diaphragm
- lumbar
- segmental branches to spinal chord
- medial sacral
- over anterior surface lower lumbar vertebrae & anterior surface of sacrum/coccyx
Describe the general path of the inferior vena cava
Identify the venous branches that drain into the inferior vena cava
formed at L5 by convergence of common iliac veins
ascends to the right of the abdominal aorta
pierces diaphragm at T8
Asymmetric
- Directly into IVC
- right gonadal
- right suprarenal
- both renal veins
- into left renal, then to IVC
- left gonadal
- leftsuprarenal
- hepatic glands right before enters diaphragm
- parietal drainage
- lumbar (3 & 4)
- inferior phrenic (paired)
Identify the drainage pattern of the ascending lumbar vein
- Receive blood from
- 1st & 2nd lumbar veins
- common iliac
- iliolumbar
- Ascending lumbar meets up with subcostal & drains into azygous (right) and hemizygous (left)
What is nutcracker syndrome?
symptoms?
treatment?
- left renal vein compression between superior mesenteric artery and abdominal aorta
- symptoms
- hmaturia
- flank pain
- left testicular pain
- varicocele (rarely)
- Treatment
- observation
- endovascular techniques
- surgery
Identify the indicated lymph nodes associated with posterior abdominal wall
- iliac lymph nodes (internal and external)
- drain into common iliac
- pre-aortic nodes (on anterior aorta)
- para-aortic nodes (right and left
- drain into lateral aortic or lumbar nodes
- cisterna chyli (L1-2)
- becomes the thoracic duct
Identify the nerves that innervate the posterior abdominal wall
Describe the innervation pattern of the subcostal nerve
- T12
- posterior to lateral arcuate ligament
- inferolaterally on anterior surface of quadratus lumborum
- motor and sensory innervation
- external oblique
- skin anterolateral abdominal wall
Describe the path of the iliohypogaastric nerve
- Fibers from L1 (muscular branches to abdominal muscles)
- Ant. surface quadratus lumborum (post. to kidneys)
- pierces transversus abdominis near ASIS
- travel between transversis abdominis & internal oblique
- branches
- laeral cutaneous (sensation flank region & post/lat glueal skin)
- anterior cutaneous (sensation to skin over pubic region)
Describe the path of the ilioinguinal nerve
- fibers from L1 (smaller than iliohypogastric)
- inferior to iliohypogastric on atn. quadratus lumborum
- along iliacus muscle towrd iliac crest
- pierces transveralis abdominis & internal oblique
- enters inguinal canal through via piercing muscles
- exits the superficial canal
- branches
- muscular innervation internal oblique
- cuteneous innervation
- superior medial thigh
- root of penis/mons pubis
- anterior scrotum/labia majora
Describe the path of the genitofemoral nerve
- fibers from L1-2
- pierces psoas major (posterior to ureter)
- branches
- genital
- through deep inguinal ring/inguinal canal
- male:
- cremasteric muscle
- skin superior/anterior scrotum
- female:
- (round ligament) pubis & labia majora
- femoral
- lateral side of iliac artery, posterior ot inguinal ligament –> pierces femoral sheath
- innervation
- skin of superior anterior thigh
- genital
Describe the path of the lateral cutaneous nerve of the thigh
- Fibers from L2-3
- emerges lateral to psoas major
- cross the iliacus & posterior to inguinal ligament on its way to the thigh
- innervation
- skin on anterior lateral thigh (to knee)
Describe the path of the obturator nerve
- Fibers from L2-4
- medial border psoas major
- travel with common iliac vessels into pelvic region
- enter the obturator foramen into the thigh
- branches (around obturator externs & adductor magnus)
- anterior
- posterior
- innervation
- cutaneous to medial thigh
- motor to 6 muscles
- articular to hip joint
Describe the path of the femoral nerve
- Fibers from L2-4
- lateral border of psoas majot
- between iliacus & psoas major
- posterior tot he inguinal ligament into the anteiror compartment of the thigh
- innervation
- cutaneous branches (ant thigh)
- muscular branches (ant. muscular compartment of thigh)
- articular branches (hip joint)
In what space do the kidneys lie?
What structure are in direct contact with each of the kidneys?
paraverebral gutters (next to the vertebrae)
- right kidney
- adrenal duodenum
- right colic (hepatic) flexure
- superior pole at rib 12 (11th intercostal space)
- left kidney
- adrenal pancreas
- left colic (splenic) flexure
- superior pole at rib 11 (10th intercostal space)
- posterior
- diaphragm
- psoas major
- quadratus lumborum
- transversus abdominis
Describe the layers that surround the kidney
fibrous capsule
perirenal fat
renal fascia: closed at diaphragm, open inferiorly
pararenal fat
Identify the arterial branches that supply the kidney
What is unique about the right renal artery?
The right renal artery passes posterior to the inferior vena cava
- Renal arteries off abdominal aorta just inferior to SMA
- segmental renal arteris near hilum
- ureteric branches
- brahes to renal capsule & adipose tissue
What is the function of the ureter?
Describe their descent
muscular tube that connects the kidenys to the bladder
posterior to renal vessels at renal pelvis
descends on psoas mjor
crosses anterior to bifurcation f common iliac artery
What are the 3 sites of relative constriction within the ureter?
Why is this clinically relevant?
- uretopelvic junction
- crossing over pelvic brin (over common iliac bifurcation)
- through wall of urinary bladder
clinically relevant b/c are potential sites of obstruction for calculi
What is the difference between venous drainage from the left and right kidneys?
left renal artery is longer
it crosses anterior to the abdominal aorta and posterior to the superior mesenteric artery
also, the left adrenal vein will dump into the left renal vein to get to the IVC, whereas the right adrenal ven will dump directly into the ICV
What are the arterial branches that supply the adrenal glands?
- Superior suprarenal
- from inferior phrenic
- middle suprarenal
- from abdominal aorta
- inferior suprarenal
- from renal
