Part II. Posterior Abdominal Wall pg 73-78 Flashcards
Long, thick and fusiform lying lateral to lumbar vertebrae
Psoas Major M
What is the superior attachment of the Psoas Major muscle?
TP’s, bodies and IVDs of vertebrae T12-L5
The psoas major muscle is crossed superiorly by what ligament?
Medial arcuate ligament of the thoracic diaphragm
Inferiorly, the psoas major muscle passes deep to what structure?
Inguinal ligament
What is the inferior attachment of psoas major muscle?
Lesser trochanter of femur with iliacus muscle
The lumbar plexus of nerves is embedded in what?
Psoas muscle
What innervates psoas major muscle?
Ventral rami of L1-L3
What is the action of psoas major muscle?
- Flexes thigh or flexes trunk
- balances trunk when upright
Large triangular muscle located lateral to inferior part of Psoas Major M
Iliacus muscle
Muscle of the posterior abdominal wall that is sometimes present (<50%) and identified by its long tendon
Psoas minor muscle
What is the superior attachment of iliacus muscle?
Ala of sacrum, iliac fossa and anterior sacroiliac ligament
What is the inferior attachment of iliacus muscle?
Lesser trochanter with psoas major muscle (iliopsoas muscle)
What is the innervation for iliacus muscle?
Femoral nerve (L2-L4)
What is the action of iliacus muscle?
Flexes thigh and stabilizes hip joint (with psoas major muscle as iliopsoas)
Quadrilateral shaped muscle forming a sheet on posterior abdominal wall
Quadratus lumborum muscle
What is the superior attachment of quadratus lumborum?
12th rib and lumbar TPs
The quadratus lumborum muscle is crossed superiorly by what ligament?
Lateral arcuate ligament
What is the inferior attachment of quadratus lumborum muscle?
Iliolumbar ligament and lumbar TP’s
Subcostal N and branches of lumbar plexus of nerves cross this muscle
Quadratus lumborum muscle
What innervates quadratus lumborum muscle?
Ventral rami of T12-L4
What is the action of quadratus lumborum muscle?
- depresses/stabilizes 12th rib to form a base for respiratory muscle movements
- laterally flexes vertebral column
What lines the internal surface of the posterior abdominal wall?
Parietal peritoneum
What tissue layer is between the parietal peritoneum and musculature?
Endoabdominal fascia
Where is the thoracolumbar fascia thickest and strongest?
Lumbar region
Where is thoracolumbar fascia thinnest and most transparent?
Thoracic region
Where does the thoracolumbar fascia attach medially?
Vertebrae and spans between 12th rib and iliac crest
Anterior, middle and posterior layers of the thoracolumbar fascia split to enclose deep back muscles. Quadratus lumborum muscle is located between which layers?
Anterior and middle layers
Anterior, middle and posterior layers of the thoracolumbar fascia split to enclose deep back muscles. Erector spinae muscle is located between what layers?
Middle and posterior layers
What attaches to the lateral aspect of the posterior layer of the thoracolumbar fascia?
Latissimus Dorsi Muscle
What attaches to the lateral thoracolumbar fascia?
- Internal oblique muscle
- Transversus abdominis muscle
The ventral ramus of T12 forms what nerve?
Subcostal N
Posteriorly, the subcostal nerve passes under _______ and crosses ________ .
- under lateral arcuate ligament of the diaphragm
- crosses quadratus lumborum muscle
NOTE: L1 also does
Laterally, subcostal nerve passes between what two muscles?
Internal oblique and transversus thoracis muscle
Dorsal rami of lumbar spinal nerves supply what muscles?
The muscles and skin on the back
The ventral rami of lumbar spinal nerve pass through this muscle to form the lumbar plexus of nerves?
Psoas major muscle
What forms the lumbar plexus?
Ventral rami of lumbar spinal nerves L1-L4
Each lumbar nerve receives what kind of fibers via grey rami communicantes?
Postsynaptic sympathetics
Ventral ramus of L1 splits to form what two nerves?
Iliohypogastric N
Ilioinguinal N
When does ventral ramus of L1 split into ilihypogastric N and ilioinguinal N?
- Proximally in psoas major muscle or distally near ASIS
Posteriorly, the VPR of L1 passes under _______ and crosses ________ .
- medial arcuate ligament of the diaphragm
- quadratus lumborum muscle
NOTE: subcostal nerve also does
The iliohypogastric N and ilioinguinal N parallel the iliac crest and pierces what muscle near the ASIS?
Transversus abdominis muscle
What do Iliohypogastric N and Ilioinguinal N innervate?
- internal abdominal oblique
- transversus abdominis muscle
- L1 dermatome anteriorly
Lateral femoral cutaneous nerve receives contributions from what ventral primary rami?
L2-L3
Where does lateral femoral cutaneous nerve pass?
Inferiolaterally across iliacus muscle
Where does lateral femoral cutaneous nerve enter the thigh?
Inferior to inguinal ligament and medial to ASIS
What does lateral femoral cutaneous nerve innervate?
Skin of anterolateral thigh
Femoral nerve receives contributions from what ventral primary rami?
L2-L3
What is the path of femoral nerve?
It emerges from the lateral border of psoas major muscle and then passes deep to inguinal ligament and into the anterior thigh
What does femoral nerve innervate?
Iliacus muscle, hip flexors and knee extensors
Genitofemoral nerve receives contributions from what ventral primary rami?
L1-L2
Where is genitofemoral nerve located?
Anterior surface of psoas major muscle
The genital branch of genitofemoral nerve passes through what?
Deep inguinal ring
What does the genital branch of genitofemoral nerve innervate?
- Anterolateral skin of scrotum/labia majora
- cremaster muscle
Femoral branch of genitofemoral nerve pass along what artery?
external iliac artery
What does the femoral branch of genitofemoral nerve innervate?
Skin over the femoral triangle
Obturator nerve receives contributions from what ventral primary rami?
L2-L4
Where is obturator nerve located?
Along medial border of psoas major muscle
What does obturator nerve innervate?
Adductor muscles of the thigh
Lumbosacral trunk receives contributions from what ventral primary rami?
L4-L5
Where is the lumbosacral trunk located?
Medial to psoas major muscle where is passes over ala of sacrum
The lumbosacral trunk participates with what ventral primary rami to form the sacral plexus of nerves?
S1-S4
The lumbar sympathetic trunk is composed of what?
4 paravertebral ganglia and associated interganglionic segments
Presynaptic sympathetics originate from the lateral horn as low as what vertebral level?
L2-L3
Presynaptic sympathetic fibers enter the sympathetic trunk via ______.
White rami communicantes
Postsynaptic sympathetics enter the lumbar ventral rami via _______.
Grey rami communicantes
Presynaptic sympathetics originating from lateral horn between T5 1- L2 or L3 from what nerve?
Abdominalpelvic splanchnic nerve
Greater splanchnic nerve arises from presynaptic sympathetics from what vertebral levels?
T5-T9
Lesser splanchnic nerve arises from presynaptic sympathetics from what vertebral levels?
T10-T11
Least splanchnic nerve arises from presynaptic sympathetics from what vertebral levels?
T12
The thoracic splanchnic nerves synapse on one of three ganglia?
Celiac
Superior mesenteric
Aorticorenal ganglia
Lumbar splanchnic nerve arises from presynaptic sympathetics from what vertebral levels?
L1 - L2 or L3
Where does the lumbar splanchnic nerve synapse?
Inferior mesenteric ganglion
Postsynaptic sympathetics exit their respective prevertebral ganglia and follow ________ into abdominal viscera.
Periarterial plexuses
The primary function of sympathetic innervation to the abdominal viscera is what?
Vasoconstriction to inhibit gastrointestinal activity
How do visceral afferent fibers from the abdominal viscera return to the CNS?
They accompany sympathetics retrograde through splanchnic nerves
What is the result of visceral afferent fibers accompaning sympathetics retrograde through splanchnic nerves?
Referred pain from the abdominal viscera is to dermatomes associated with segmental levels where
presynaptic sympathetics originate
What nerve is derived from ventral primary rami of S2-S4 and conveys presynaptic parasympathetic to the hypogastric plexuses?
Pelvic splanchnic nerve
NOTE: no association with sympathetic innervation
The pelvic splanchnic nerve provides parasympathetic innervation to where?
Hypogastric plexus from splenic flexure of colon to rectum and pelvic viscera
Presynaptic parasympathetics from pelvic splanchnic nerve synapse on postsynaptic cells in which ganglia?
Intrinsic ganglia
Parasympathetic innervation by pelvic splanchnic nerve stimulates what?
Gastrointestinal activity
The autonomic plexuses of the posterior abdominal wall surround the _________ and contain both sympathetic and parasympathetic neurons
abdominal aorta and/or its branches
The celiac plexus receives sympathetic contribution from where?
Greater and lesser splanchnic nerve
The celiac plexus receives parasympathetic contribution from where?
Posterior vagal trunk
The celiac plexus provides autonomic innervation primarily to what?
Foregut derivatives
What provides parasympathetic innervation from lower esophagus to splenic flexure?
Anterior and posterior vagal trunks
Where do the anterior and posterior vagal trunks emerged from?
esophageal plexus and pass through esophageal hiatus
The superior mesenteric plexus receives sympathetic contribution from where?
Lesser and least splanchnic nerves
The superior mesenteric plexus receives parasympathetic contribution from where?
Posterior vagal trunk
Superior mesenteric plexus provides autonomic innervation primarily to what?
Midgut derivatives
The inferior mesenteric plexus receives sympathetic contribution from where?
Lumbar splanchnic nerve
The inferior mesenteric plexus receives parasympathetic contribution from where?
Pelvic splanchnic nerve
Inferior mesenteric plexus provides autonomic innervation primarily to what?
Hindgut derivatives
The superior hypogastric plexus receives sympathetic contribution from where?
Lumbar splanchnic nerve
The superior hypogastric plexus receives parasympathetic contribution from where?
Pelvic splanchnic nerve
The superior hypogastric plexus is connected to inferior hypogastric plexus by what nerves?
Hypogastric nerves
The inferior hypogastric plexus receives sympathetic contribution from where?
Lumbar splanchnic nerve
The inferior hypogastric plexus receives parasympathetic contribution from where?
Pelvic splanchnic nerve
Superior and inferior hypogastric plexuses (connected via hypogastric nerves) provide autonomic innervation to what?
Pelvic plexuses and viscera
The abdominal aorta has 3 unpaired anterior visceral branches. What are they and what vertebral level do they branch at?
- Celiac Trunk (T12)
- Superior Mesenteric A (L1)
- Inferior Mesenteric A (L3)
The abdominal aorta has 3 paired lateral visceral branches. What are they and at what vertebral level to do they branch?
- Middle Suprarenal A (L1)
- Renal A (L1)
- Gonadal A (Testicular A or Ovarian A) (L2)
The abdominal aorta has 3 paired parietal branches. What are they and what vertebral level do they branch at?
- Subcostal A (T12)
- Inferior Phrenic A (T12)
- Lumbar A (L1-L4)
The abdominal aorta bifurcates at what vertebral level? What does it form at the bifurcation?
At L4, bifurcates into R/L Common Iliac A
What external landmark can be used to determine the approximate level of abdominal aorta bifurcation?
about 2-3cm inferior to umbilicus at level of iliac crests
Other than the right and left common iliac artery, what other artery originates at the bifurcation of the abdominal aorta?
Median sacral artery
The abdominal aorta runs anterior to vertebral bodies between what vertebral levels?
T12 - L4
The common iliac artery follows the medial border of what muscle to the pelvic brim?
Psoas major muscle
The common iliac artery bifurcates where? To form what arteries?
Bifurcates at the Belgic brim to form external and internal iliac artery
What is the principle blood supply to the pelvis, gluteal region and perineum?
Internal iliac artery
External iliac artery follows ______ muscle deep to inguinal ligament, where it becomes ______ artery.
- Ilipsoas muscle
- femoral artery
Inferior epigastric artery and deep circumflex artery are branches of what?
Femoral artery
What provides venous return from lower limbs, back, abdominal walls and pelvic viscera?
Inferior vena cava
Does the inferior vena cava have valves?
No valves (except nonfunctional one at orifice in R Atrium)
Venous return from the abdominal viscera passes through what before entering the inferior vena cava?
Hepatic portal vein
Venous return from the abdominal viscera passes through the hepatic portal vein and then enters the vena cava through what?
Hepatic veins exiting the liver
What vertebral level does the inferior vena cava begin?
L5
The inferior vena cava is formed by the union of what vessels?
Common iliac veins, anterior to L5
The union of common iliac veins to form inferior vena cava occurs where in relation to the aortic bifurcation?
Slightly inferior and right
The inferior vena cava ascends along _____ side of vertebrae to _____ opening in diaphragm
- right
- caval
Tributaries to the inferior vena cava include:
- common iliac veins
- lumbar veins
- R gonadal V
- Renal vein
- R suprarenal vein
- R inferior phrenic vein
- hepatic vein
- azygos/hemiazygos veins
The abdominal venous drainage has asymmetry due to the vena cava being positioned on the right side of the vertebrae instead of midline. Describe this asymmetry.
The right gonadal, suprarenal and inferior phrenic veins drain directly into the inferior vena cava
The left gonadal, suprarenal and inferior phrenic veins drain into the left renal artery before draining into the inferior vena cava
All lymphatics below the diaphragm including those from the lower limbs and abdomen converge to form what?
Chyle cistern
NOTE: Often appears as a plexus of vessels rather than a dilated sac
Where are lymph nodes of the posterior abdominal wall located?
Along abdominal aorta and its main branches
Inguinal lymph nodes primarily drain what structures?
- Lower limbs
- Perineum
- Buttocks
- Lower part of anterior abdominal wall
Inguinal nodes drain secondarily through what?
external and common iliac nodes
Internal iliac nodes primarily drain what structures?
- Pelvic urinary organs
- Pelvic genital organs
- Pelvic portion of rectum
Internal iliac nodes drain secondarily through what?
either common iliac or lumbar nodes
Lumbar lymph nodes primary drain what structures?
- Posterior body wall
- Kidneys and suprarenal glands
- Gonads (testes/ovaries)
What nodes drain to the lumbar nodes?
- Common iliac
- inferior mesenteric
- superior mesenteric
- celiac nodes
What is the chyle cistern?
The lower expanded beginning of the thoracic duct to which lymphatics from lower limbs and abdomen converge
Where is the chyle cistern located?
At L1 between the R crus of the diaphragm and abdominal aorta