Intro to Abdomen Flashcards
Describe abdomen
Below diaphragm
Region of the trunk between thorax and pelvis
Composed of abdominal wall and cavity
Describe borders of abdomen
Superior = inferior thoracic aperture - closed by thoracic diaphragm
Inferior = pelvic inlet (pelvis narrows down, abd region continuous with pelvic organs)
Describe abdominal wall
Partly compared of bones (few), mostly muscles
(Not like thorax - has many ribs)
Describe abdominal cavity
Houses major elements of gi, spleen and part of urinary system
Lined by peritoneum (serous sac of gi organs), contains much of viscera
Describe bones of abdominal wall
Vertebrae = 5 lumbar vertebrae
Pelvis = superior aspect pelvic bone (false pelvis, *iliac bones)
Thorax = costal margin, ribs 11-12, xiphoid process
Describe fascia of abdominal wall
Superficial fascia = under skin (fatty layer=camper’s fascia)
Transversalis fascia = deep to abdominal muscles (thin, between inner layer of muscles and peritoneum)
Describe organization of muscles of abdominal wall
Muscles seal it
Posterior
Lateral a
Anterior
Describe posterior muscles of abdominal wall
Quadratus lumborum = square muscle at back
Psoas
Iliacus
Describe lateral muscles of abdominal wall
(Same organization as thoracic muscles)
External oblique = superficial, sup and lat to inf and medial
Internal oblique = middle layer, inf and lat to sup and medial (same as int intercostal muscle)
Transversus abdominis = innermost, transverse direction
Describe anterior muscles of abdominal wall
Recuts abdominis incased in recuts sheath (straight muscles in front, 6 pack)
Describe rectus sheath
Tendinous sheath formed by layering of aponeuroses (flat tendon) of ext oblique, int oblique and transversus abdominis
Describe distribution of aponeuroses of abdominal muscles and rectus sheath
Differs= above and below arcuate line
Describe above arcuate line
Anterior aspect =external and 1/2 internal
Posterior aspect = 1/2 internal and transversus (Lies against transversalis fascia)
(Makes rectus sheath = where muscle can slide, in between the 2 layers of internal - splits)
Describe below arcuate line
All aponeurosis move anterior to rectus abdominis = ext, internal, transversus, rectus abdominis - lays on transversalis fascia
Transition makes arch of fibres = arcuate line
Where is best to cut for c section
Below arcuate line since one layer
Where is arcuate line
Midway between umbilicus and pubic symphysis
What is aponeurosis of rectus muscles called - in middle of abd
Linea alba
What is inguinal ligament
Thickening of inferior border of ext oblique
From anterior superior iliac spine (asis) to Pubic tubercle
What is purpose of inguinal canal
Important passengers for structures
Like testicular structures for men - structures to reach scrotum
Describe formation of inguinal ligament= generally, informal
Where ext oblique inserts and jumps and bony insertions = gets thicker= forms inguinal ligament - more solid insertion of lower ext oblique between 2 points (asis and pubic tubercle)
Describe inguinal canal - length
4 cm long approx
Describe borders of inguinal Canal
Anterior wall = aponeurosis ext oblique (continuation)
Roof = int oblique (jumps and inserts medially) and transversus abdominis
Posterior wall = transversalis fascia
Floor = inguinal ligament
What forms superficial inguinal ring
Anterior wall of inguinal canal = aponeurosis ext oblique (continuation)
What forms deep inguinal ring
Posterior wall inguinal canal = transversalis fascia
Describe motor and sensory innervation - nv abd wall = what is innervated
Skin, abdominal muscles and parietal peritoneum
Name nerves that innervate abd wall
Thoracoabdominal nerves = t7-t11, (leaves intercostal space and reach abd region, segmental organization, laterally)
Subcostal nerve = t12 and l1
Ilioihypogastric = t12 and l1
What is umbilical level
T10
What innervates diaphragmatic peritoneum
Phrenic nerve
Describe innervation of visceral peritoneum
By visceral afferents
Poor localization of sensation= can lead to referred pain
Where does arterial supply of abd wall come from
Internal thoracic arteries
External iliac arteries
Describe branches of internal thoracic arteries = nv abd wall
Musculophrenic = along costal margin
Superior epigastric = travels post to rectus abdominis (sup to stomach, slides in rectus sheath and feeds abdominus)
Describe branches of external iliac arteries = nv abd wall
Inferior epigastric = travels post to rectus abdominus
Will anastomose with superior epigastric artery
Are visceral and parietal peritoneum both sensory
No
Visceral = not sensory
Parietal = sensory by nerves for that region (thoracoabdominal)
Describe body cavities
Human body = fluid filled space
Organs organized, separate and protected - supported by means of fascia
Allow movement between organs and surrounding structures
Describe cavities lining = gen
Serous membrane lines thoracic and abdominopelvic cavities and their content
Continuous but divided into 2 layers
Describe specific layers of cavities lining
Parietal layer = forms outer wall of cavity, attached organs to their walls
Visceral layer = reflection from parietal, overs and encloses viscera (not innervated much for sensory)
Between layers = space filled by serous fluid that allows sliding
What is peritoneum
Similar to pleura and serous pericardium
Continuous epithelial like layer, divided into 2
Describe layers of peritoneum
Parietal = lines abdominal wall
Space between parietal and visceral = peritoneal cavity (forms sac)
Visceral = covers organs
What does parietal peritoneum do
Reflects off abdominal wall and folds to become a components of mesenteries that suspend viscera
Mesentery = not on wall or organ, anchors to wall, contains vessels, not parietal or visceral
Describe Intra vs retro peritoneal concept
Abdominal viscera = suspended in peritoneal cavity by folds of peritoneum (mesenteries) - INTRA or outside peritoneal cavity (part of organ covered by peritoneum)- RETRO
What are omenta, mesenteries and ligaments - gen
PERITONEAL cavity has numerous peritoneal folds
Connect organs to each other or abdominal wall
Describe omenta
Greater and lesser
Double layer peritoneum
From stomach to duodenum and other viscera
Describe omental sacs
2 omenta divide abdominal cavities =
Greater (rest) and lesser (behind liver and stomach) omental sacs
What are mesenteries = specifics
Peritoneal folds attaching viscera to post abd wall
Allows movements and conduit for neurovascular structures
Name mesenteries
Mesentery = small intestine
Transverse mesocolon = transverse colon
Sigmoid mesocolon = sigmoid colon
What is peritoneal ligament
Double layer peritoneum connecting organs to each other or to body wall
No nv structures in here
Describe greater omentum
Large apron like peritoneal fold, protects and covers organs, big curtains
from greater curvature stomach, drapes over transverse colon and inserts back up on transverse colon
Describe lesser omentum
anchors stomach
from lesser curvature stomach and 1st portion duodenum to visceral surface liver
Describe hepatoduodenal ligament
Lesser omentum
thicker portion from liver to duodenum
fot structures to porta hepatis (bile duct, portal vein hepatic proper artery)
Describe hepatogastric ligament
Lesser omentum
thinner portion from liver to lesser curvature stomach
Describe visceral part of peripheral nervous system
innervates blood vessels, glands, smooth muscle and cardiac muscle
consists of 3 divisions = sympathetic, parasym and enteric
Describe ans = gen
2 neuron pathway between cns and target organ
proximal preganglionic (presynaptic) neuron
distal postganglionic (postsynaptic neuron)
Describe 3 features ans
- cell body of preganglionic neuron located in cns
- preganglionic neuron synapse with a postganglionic neuron in autonomic ganglion
- postganglionic neuron reaches target organ
Describe psns - nerves
presynaptic long
postsynaptic short and associated with target organ
cranial nerves= 3, 7, 9,10
sacral nerves = s2,3,4
Describe sns - nerves
presynaptic short
postsynaptic long
more balanced than psns tho
vertebral level of t1-l2
*synapse in ganglion, usually in abd aorta, region, synapse further away from target organ
Where do parasympathetic nerves arise from
brain-brainstem and sacral spinal cord segments s2,3,4
Describe the psns that arise from brain/brainstem
preganglionic fibers from cranial nerves =
cn 3,7,9,10
Describe psns that arise from sacral spinal cord
from pelvic splanchnic nerves
contribute to autonomic plexuses in pelvis, abdomen
Describe terminal synapse psns
terminal synapse in a parasympathetic ganglion that is always located near/in target organ
Describe splanchnic nerves - Gen, psns
visceral nerves carrying presynpatic fibers of ans
Describe sns = arise from
spinal cord of thoracic and lumbar level t1-l2
Describe sns = fibers
preganglionic fibers leave the spine with spinal nerve of corresponding level
enter sympathetic trunk via white rami communicant
will use 3 diff options to reach sympathetic ganglion
Name the 2 groups of sympathetic ganglia
sympathetic trunk
prevertebral ganglions
Describe sympathetic trunk = sympathetic ganglia
located on each side of spine
connected = forms chain, cranium to coccyx
Describe prevertebral ganglions = sympathetic ganglia
located on main breaches from aorta
coeliac, superior mesenteric, inferior mesenteric, aorticorenal
Where does sns receive preganglionic fibers from
from thoracic splanchnic nerves
Describe how preganglionic neurons reach sympathetic ganglion = sympathetic trunk, same level
will synapse in ganglion of sympathetic trunk at corresponding level (use gray rami communicans)to re enter spinal nerve and reach target organ
Synapse on chain at same level
Describe how preganglionic neurons reach sympathetic ganglion = sympathetic trunk, diff levels
Will travel up or down in trunk before synapsing in ganglion (use gray rami communicans) to re enter spinal nerve and reach target organ
Synapse at level it wants to leave
Describe how preganglionic neurons reach sympathetic ganglion = to prevertebral ganglia = using splanchnic nerves
Will not synapse in any ganglion of sympathetic trunk and will reach a prevertebral ganglion by using a splanchnic nerve
For viscera, presynaptic chain reaches but then leads away = splanchnic
Presynaptic sympathetic neurons that will bring sympathetic input close to organ in abd region, synapse here and reach target organ
What is thoracic splanchnic
Pass from sympathetic trunk in thorax to prevertebral plexus and ganglia
Pass through diaphragm Crura
Name the 3 splanchnic nerves
Greater splanchnic
Lesser splanchnic
Least splanchnic
Describe where greater splanchnic goes
T5-t9
To celiac ganglion associated with celiac trunk
Describe where lesser splanchnic goes
T10-11
To aorticorenal and superior mesenteric ganglia
Describe where least splanchnic goes
T12
To renal plexus
