Case 7 Anatomy Flashcards
what is the posterior abdominal wall formed by?
- lumbar vertebrae
- their intervertebral discs
- diaphragm
- psoas muscle
- iliacus muscle
- quadratus lumborum muscles
- thoracolumbar fascia
(large area of connective tissue – roughly diamond-shaped – which comprises the thoracic and lumbar parts of the deep fascia enclosing the intrinsic back muscles)
describe a typical lumbar vertebra
- Has massive, kidney-shaped body
- Has triangular vertebral foramen
- Does not have short, broad transverse processes (long and slender) ?
- Does not have long downward pointing spinous processes (short and broad) ?
- Had medially facing superior articular facets
- Has laterally facing inferiorly articular facets
describe the different movements of the spinal column
- Flexion = bending of the vertebral column in an anterior direction
- Extension = bending of the vertebral column in a posterior direction
- Lateral flexion = bending of the vertebral column to one side
- Lateral extension = returning of the vertebral column to an upright position following lateral flexion
- Rotation = twisting of the vertebral column
- Circumduction = a combination of all movements
which movement is the least extensive in the lumbar region?
rotation
which muscles are involved in flexion of the lumbar spine?
psoas major and rectus abdominis
which muscles are involved in extension of the lumbar spine?
postvertebral muscles
which muscles are involved in lateral flexion of the lumbar spine?
external oblique, internal oblique and postvertebral muscles
describe the diaphragm
- Central tendon
- Caval opening (most anterior)
- Oesophageal hiatus
- Aortic hiatus (most posterior)
- Median arcuate ligament (connects the right and left crura)
- Right crus
- Left crus
- Medial arcuate ligament (tendinous fascia that arches over the psoas major muscle as it passes through the diaphragm – lies between the lateral arcuate ligament and the midline median arcuate ligament)
- Lateral arcuate ligament (arches across the upper part of the quadratus lumborum muscle)
what can the peripheral attachments of the muscular part of the diaphragm be divided into?
three parts: sternal, costal and lumbar
where does the right crus arise from?
the first three or four lumbar vertebrae
which crus is lower?
right, like the right kidney is lower down
where does the left crus arise from?
the first two or three lumbar vertbrae
what is the median arcuate ligament?
fibrous structure that unites the right and left crura
what is the medial arcuate ligament? where does it extend from and to?
- thickening of the fascia (superior part) that covers the psoas major muscle
- extends from the body to the tip of the transverse process of L1
what is the lateral arcuate ligament? where does it extend from and to?
- thickening of the fascia (superior part) that covers the quadratus lumborum muscle
- extends from the transverse process of T12 to the 12th rib
what forms the aortic hiatus?
right and left crura and the median arcuate ligament
at what level is the caval opening?
T8
at what level is the aortic hiatus?
T12
at what level is the oesophageal hiatus?
T10
what goes through the caval opening?
- Right phrenic nerve
* IVC
what goes through the oesophageal hiatus?
- Oesophagus
- Right and left vagi
- Oesophageal branches of left gastric artery
- Lymphatics from oesophagus
what goes through the aortic hiatus?
- Thoracic duct
- Aorta
- Azygos vein
what are the muscles of the posterior abdominal wall?
- Psoas major
- Iliacus
- Quadratus lumborum
the tendons of the psoas major and iliacus muscles unit and insert onto where?
lesser trochanter of the femur
where does the psoas major muscle arise from?
bodies and transverse processes of T12-L5 vertebra and the intervening discs
what do the psoas major and iliacus muscles combine to form and what does this do?
- iliopsoas muscle
- main flexor of the hip joint
what does the quadratus lumborum do during inspiration?
fixes the 12th rib
where does the iliacus originate from?
iliac fossa (upper 2/3 of iliac fossa, internal lip of iliac crest, lateral aspect of sacrum, ventral sacroiliac ligament and lower portion of iliolumbar ligament)
what is the iliacus innervated by?
femoral nerve
what is psoas major innervated by?
(psoas major is innervation by anterior rami of L1-3)
what is the internal aspect of the abdominal wall covered with? where does this lie?
fascia which lies between the parietal peritoneum and the muscle
what are the psoas and iliacus covered by?
endoabdominal fascia
what is the endoabdominal fascia continuous with where?
- diaphragmatic fascia superiorly
- transversalis fascia laterally
what is the quadratus lumborum covered by?
thoracolumbar fascia
where do the main vessels of the posterior abdominal wall lie?
anterior to the bodies of the lumbar vertebrae
where does the abdominal aorta begin and end? what levels?
- Begins at the aortic hiatus at the level of T12 and ends by bifurcating into the right and left common iliac arteries
- Bifurcation of the aorta occurs at L4
what are the posterior relations of the abdominal aorta?
- The abdominal aorta lies in front of the bodies of T12-L4
* The lumbar veins cross behind the aorta on route to the vena cava
what are the right lateral relations of the abdominal aorta?
- Inferior vena cava
- Azygos vein
- Cisterna chyli
- Right coeliac ganglion
- Right crus of diaphragm
- Thoracic duct
what are the left lateral relations of the abdominal aorta?
- Left crus of diaphragm
- Left coeliac ganglion
- Left sympathetic chain (not on right side because that’s on the right of the IVC)
what are the anterior relations of the abdominal aorta? (superior to inferior)
- Coeliac plexus and ganglion
- Body of pancreas and splenic vein
- Left renal vein
- Horizontal part of duodenum
what can the branches of the aorta be divided into?
- unpaired visceral
- paired visceral
- paired parietal
where does each division of branches of aorta arise from?
- Unpaired visceral = ventral plane
- Paired visceral = lateral plane
- Paired parietal = posterolateral plane
what are the unpaired visceral branches?
- Coeliac trunk
- Superior mesenteric artery
- Inferior mesenteric artery
what are the paired visceral branches?
- Gonadal artery
- Suprarenal artery
- Renal artery
what are the paired parietal branches?
- Inferior phrenic artery
- Lumbar artery
- Subcostal artery
what is the order of the branches of the abdominal aorta branches?
(- Subcostal) - Inferior phrenic - Coeliac trunk - Superior & middle suprarenal - Superior mesenteric - Renal - Gonadal - Inferior mesenteric - Median sacral (with lumbar arteries throughout)
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the common iliac veins unite to form what?
IVC
where is the IVC formed?
at L5 (bifurcation of aorta at L4)
what is the median sacral vein?
a tributary of the IVC at its origin
where is the IVC in relation to the aorta?
ascends on right side of aorta
where does the IVC exit the abdomen?
T8 be piercing the diaphragm
what runs on the right-hand side of the IVC?
- right sympathetic trunk
- right ureter
what runs on the left-hand side of the IVC?
- aorta
- cisterna chyli
which organs sit directly in front of the IVC?
- liver
- duodenum
- pancreas
what crosses the IVC anteriorly?
- portal triad within the lower free edge of the lesser omentum
- right gonadal artery
- right common iliac artery
what are important structures passing behind the IVC?
- right renal artery
- azygos vein
what is the relation between the IVC and the epiploic foramen?
IVC forms the posterior boundary of epiploic foramen
how many hepatic veins? what do they drain into?
a triplet of vessels which drain into the anterior aspect of the IVC
what are the lateral visceral tributaries of the IVC?
- right and left renal veins
- right gonadal vein
- right suprarenal vein
what does the left gonadal drain into?
left renal vein
what does the left suprarenal vein drain into?
left renal vein
what are the lateral tributaires of the IVC that supply the abdominal wall?
- four pairs of lumbar veins
- inferior phrenic veins
what do many abdominal veins drain via?
the hepatic portal system rather than directly into the vena cava
what forms the hepatic portal vein?
splenic vein unites with superior mesenteric vessel to form it
where does the inferior mesenteric vein deliver venous blood from and to?
from hindgut to splenic vein
where are the pre-aortic nodes located? what are they named?
- close to the ventral branches of the abdominal aorta
- named accordingly as the coeliac, superior mesenteric and inferior mesenteric nodes
what do the pre-aortic nodes drain?
- The coeliac nodes drain the foregut
- The superior mesenteric nodes drain the midgut
- The inferior mesenteric nodes drain the hindgut
what do efferent vessels from the pre-aortic nodes drain into?
intestinal trunk
where do the lateral aortic (para-aortic or lumbar) nodes lie?
lateral to the abdominal aorta
what do the lateral aortic nodes drain lymph from?
- common iliac nodes
- fundus of uterus
- gonads
- kidneys
- suprarenal glands
what do efferent vessels from the lateral aortic nodes drain into?
the lumbar trunk
where do the lumbar and intestinal trunks drain into?
inferior end of thoracic duct
what is at the inferior end of thoracic duct in some individuals?
enlarged part = cisterna chyli
where does the thoracic duct drain into?
drains into the venous system at the junction of the left subclavian and left internal jugular veins
what innervation is associated with the posterior abdominal wall?
both somatic and autonomic innervation
what is the somatic innervation of the muscles and skin of the back?
dorsal rami of L1-5
what do the ventral rami form?
(L1-4) form the lumbar plexus and supply the muscles and skin of the inferior aspect of the trunk and the lower limb
what do the ventral rami receive from the sympathetic chain?
grey rami communicantes
what do L1 and L2 give off to the sympathetic chain?
white rami communicantes
what are the roots of the femoral nerve and what does it supply?
L2-4
- muscles in anterior compartment of thigh
- hip
- knee joints
- skin
what are the roots of the obturator nerve and what does it supply?
L2-4
- medial thigh muscles
- hip
- skin
what are the roots of the lumbosacral trunk?
L4-5
what does the lumbosacral trunk unite with to form the sacral plexus?
anterior rami of S1-4
what is the root of ilioinguinal nerve and what does it supply?
L1
- internal oblique muscle
- transversus abdominis muscle
- skin over lower inguinal region, mons pubis, anterior scrotum or labia majora and adjacent medial thigh
what is the root of the iliohypogastric nerve and what does it supply?
L1
- internal oblique muscle
- transversus abdominis muscle
- skin over iliac crest, upper inguinal and hypogastric regions
what are the roots of the lateral cutaneous nerve of the thigh and what does it supply?
L2-3
- skin on anterolateral surface of thigh
what are the roots of the genitofemoral nerve and what does it supply?
L1-2
- skin over lateral part of femoral triangle, labia majora or anterior scrotum and cremaster muscle
what do the networks of sympathetic and parasympathetic nerve fibres surround? where do they continue to?
surround the aorta and continue into pelvis below its bifurcation
what do these plexuses contain?
- pre & postganglionic sympathetic fibres
- prevertebral sympathetic ganglia
- preganglionic parasympathetic fibres
(of vagus and pelvic splanchnic nerves) - visceral afferent fibres
what are the autonomic plexuses?
- coeliac
- superior mesenteric (continuation of lower part of coeliac plexus)
- inferior mesenteric (derived chiefly from the aortic plexus)
- intermesenteric (plexus on abdominal aorta)
- superior and inferior hypogastric plexuses
what are the sympathetic splanchnic nerves?
- greater splanchnic nerve
- lesser splanchnic nerve
- least splanchnic nerve
- lumbar splanchnic nerve
greater splanchnic nerve
- where arise from
- what synapses with and where
- what innervates
- Arises from spinal cord segment T5-9
- Synapses with postganglionic neurone in coeliac ganglion
- Postganglionic fibres innervate foregut structures
lesser splanchnic nerve
- where arise from
- what synapses with and where
- what innervates
- Arises from spinal cord segment T10-11
- Synapses with postganglionic neurone in superior mesenteric ganglion
- Postganglionic fibres innervate midgut structures
least splanchnic nerve
- where arises from
- what synapses with and where
- what innervates
- Arises from spinal cord segment T12
- Synapses with postganglionic neurone in aorticorenal ganglion
- Postganglionic fibres innervate kidneys and suprarenal glands
lumbar splanchnic nerve
- where arises from
- what synapses with and where
- what innervates
- Arises from spinal cord segment L1-3
- Synapses with postganglionic neurone in inferior mesenteric ganglion
- Postganglionic fibres innervate hindgut structures
parasympathetic splanchnic nerves
- where preganglionic fibres arise from
- what pass in
- carry what fibres through what
- what synapse with and where
- Parasympathetic preganglionic fibres arise from spinal cord segments S2-4 and pass in the pelvic splanchnic nerves
- They carry preganglionic parasympathetic fibres through the inferior hypogastric plexus
- The fibres terminate by synapsing with postganglionic fibres close to, or in the walls of, the structures that they are innervating
(inferior hypogastric plexus usually contains parasympathetic fibers that originate in the ventral roots of S2-4 and travel as the slender nervi erigentes (pelvic splanchnic nerves) through the inferior hypogastric plexus to the superior hypogastric plexus)
visceral afferent fibres are conveyed back to the CNS, what do they run with in which direction?
with autonomic efferent fibres but in the opposite direction (towards, rather than from, the spinal cord)
what are visceral afferent pain fibres carried with?
the sympathetic nervous system
what are visceral reflex afferent fibres carried with?
the parasympathetic nervous system
