Abdomen Flashcards
What is contained within abdominal wall?
- Skin
- SQ fat
- three flat muscles
- transversalis fascia
- parietal peritoneum
- viscera of abdominal cavity
What are the 3 flat muscles within the abdominal wall?
- External oblique
- Internal oblique
- Transversus abdominis
What is the rectus sheath?
- Aponeurosis (common tendon) formed from external oblique, internal oblique, transverse abdominis, that encloses the
- rectus abdominis muscle
- pyramidalis muscle
- superior and inferior epigastric vessels
- thoraco-abdominal (intercostal nerves) and subcostal nerves
What is the linea alba?
Runs from xiphoid to pubic symphysis
A/I of external oblique?
Internal oblique?
Action: compresses and support absominal viscera; flex and rotate trunk
Innervation: thoraco-abdominal nerves (anterior rami T7-T11) AKA Intercostal nerves
and subcostal nerves (T12)
same for internal oblique! except innervation is also done by 1st lumbar nerve
A/I of transversus abdominis?
Action: compresses and supports abdominal viscera
Innervation: thoraco-abdominal nerves (anterior rami T7-T11) AKA Intercostal nerves
and subcostal nerves (T12)
aA/I of rectus abdominis?
Action: flexes trunk (lumbar vertebrae), and compresses abdominal viscera; stabilizes and controls tilt of pelvis
Innervation:
thoraco-abdominal nerves (anterior rami T7-T12) AKA Intercostal nerves
and subcostal nerves (T12)
A/I of pyramidalis?
Action: tenses linea alba; absent in 20% people
Innervation: subcostal nerve (anterior rami T12)
A/I psoas major/minor?
Action: flexes thigh, flexes vertebral column
Innervation: lumbar plexus (L2-L4)
/A/I Iliacus
Action: flexes thigh and stabilizes hip joint
Innervation: femoral nerve L2-L4
A/I Quadratus lumborum?
Action: Extends and laterally flexes vertebral colun; fixes 12th rib with inspiration
Innervation: anterior branches of T12, and L1-L4
How is the abdominal wall innervation?
- Lateral and anterior cutaneous branches of thoraco-abdmoinal nerves (anterior rami T7-T11 aka intercostal nerves)
- Subcostal (anterior rami T12)
- Iliohypogastric nerve (anterior rami L1)
- Ilio-inguinal nerve (ant rami L1)
come between internal and external
What is a transversus abdominis plane block?
- Targets intercostal nerves (below T6), subcostal, ilioinguinal and iliohypogastric nerves
What is the superior epigastric artery?
- Terminal branch of internal thoracic artery
- once it reaches border of rib, becomes superior epigastric
- Runs in rectus sheath and anastomose with inferior epigastric artery
What is the inferior epigastric artery?
- Branch of external iliac artery
- Runs in rectus sheath
What is deep circumflex iliac artery?
Branch of external iliac artery
run in layer with nerves (sup to transverse abdominis but deep internal oblique)
What is the thoraco-epigastric vein?
- Provides collateral pathway to SVC if IVC is blocked
- turnes into lateral thoracic vein
If inferior epigastric artery/vein is injured below arcuate vein, what can happen?
Patient can bleed out
If arterial injury above arcuate line, rectus abdominis acts as a tamponade
What is the peritoneum peitoneal cavity?
- 2 continuous layers
- Parietal peritoneum
- lines internal surface of abdominopelvic wall
- Visceral peritoneum
- invests viscera
- filled with peritoneal fluid to decrease friction, contains leukocytes and antibodies
- We have intraperitoneal, extraperitoenal, retroperitoneal and subperitoneal organs
What are our intraperitoneal organs?
- Almost completely covered wiht visceral peritoneum
- ex: stomach, spleen
What is the main characteristic of extraperitoenal, retroperitoneal and subperitoneal organs?
Outside peritoneal cavity, usually only covered on one surface by peritoneum
What are are retroperitoneal organs?
- Suprarenal glands
- Aorta/inferior vena cava
- Duodenum
- Pancreas (tail in intraperitoneal)
- ureters
- colon (ascending and descending only)
- kidneys
- esophagus
- rectum
SAD PUCKER
What is blood/nerve innervation to pareital peritoneum?
- Same blood supply and somatic nerves as region of abdominopelvic wall it lines
- umbilicue- T10
- Feels same things our skin would feel
- senstivie to heat, pressure, pain cold–> well localized
What is the blood supply and inntervation for visercal peritoneum?
What is the visceral peritoneum sensitive to and insensitive to?
- Same blood supply and visceral nerve supply as organ it covers
- ie, vagus for up to left colonic flexure, can cause bradycardia upon insufflation of belly
- Insensitive to touch, heat, cold and laceration
- Sensitive to stretching, and chemical irritation
- Pain poorly localized and referred to dermatomes
What is the pain/dermatom relationships in visceral peritoneum?
What organs are reffered to epigastric reigon?
Umbilical region?
Pubic region?
- Pharynx, esophagus, stomach referred to epigastric region
- Small intestine, cecum, appendix and ascending colon referred to umbilical region
- descending and sigmoid colon referred to pubic region
What is the omentum?
- Double layered extension of peritoneum
- greater and lesser omentums
- greater- big curtain over small/large intestine
- lesser- runs between liver and stomach
- highly mobile
- just made the omentum an organ
What is the mesentery?
- Double layer of periteonum that occurs as result of invagination of periteonum and an organ
- Provide means for neurovascular communication b/w organ and body wall
- Viscera with mesentery are highly mobile
What is the innervation pathway for presynaptic sympathetic fibers in the abdomen?
- Begins from intermediolateral cell column of gray matter of spinal cord T5-L2
- Pass through anterior roots, anterior rami and white communicating branches of T5-L2 to reach sympathetic trunks
- Pass through paravertebral ganglia of sympathetic trunks (without synapsing) to enter abomino pelvic splanchnic nerves
- greater, lesser and least thoracic splanchnic nerves
- lumbar splanchnic nerves
- Abdominopelvic splanchnic nerves conveyed to prevertebral ganglia of abdominal cavity
- celiac ganglion
- aorticorenal ganglia
- superior mesenteric ganglia
- inferior mesenteric ganglia
- ganglia names in relation to artery they’re attached to
- SYNAPSE in ganglion!
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What is pathway of post-synaptic sympathetic fibers in abdomen?
Pass from prevertebral ganglia to abdominal viscera through the periarterial plexuses associated with branches of the abominal aorta
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What organs have postsynaptic sympathetic nerves travelling along celiac artery plexus?
Gallbladder, liver, stomach, spleen, part of pancreas
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What organs have post-synaptic sympathetic nerves travelling along the superior mesenteric artery plexus?
Small intestine up to left colonic flexure
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What organs have post synaptic sympathetic fibers traveling along inferior mesenteric artery?
left colonic flexure, down to rectum
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What is the role of visceral afferent fibers in referred pain?
Convey referred pain sensations
-
accompany sympathetic fibers in retrograde fashion
- pass along spanchnic nerves to sympathetic trunk and through white rami communicantes to anterior rami
- enter post root to spinal cord
- From sigmoid to rectum, visceral pain fibers run with PSNS fibers to S2-S4 sensory ganglia and spinal cord
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Where are stomach referred pains conveyed?
T8-T12 dermatomes
relayed back via sympathetic nerves
Where is the referred pain to small intestine to transverse colon conveyed?
T8-T12 dermatomes via sympathetic nerve pathways
Where are referred pains from descending colon conveyed?
Referred to T12-L2 dermatomes
carried back on sympathetic fibers
Where do visceral pain fibers from sigmoid to rectum run to?
Travel via PARAYMPATHETIC FIBERS (different!) to S2-S4 sensory ganglia and then spinal cord
What nerves do afferent fibers from liver/gallbladder run on?
Phrenic and intercostal nerves (on somatic afferent fibers) (DIFFERENT!)
- This is what causes pain in neck. Phrenic nerve originated C3-C5, body can’t tell where sensory pathways coming from exactly, causes referred pain
- Gall bladder irritation causes referred shoulder pain
What is pathway for parasympathetic abdominal innervation for vagus nerve?
provides PSNS innervation for all abdomen until left colonic flexure
- travels along esophagus, spleen, pancreas, liver, gallbladder, then travels BACK via celiac artery plexus, goes on to travel to superior mesenteric artery plexus to innervate small intestine and colon up until left colonic flexure
- you have anterior and posterior vagal trunks
- presynaptic synapse with postsynaptic neurons lying on or within abdominal viscera until the left colonic flexure
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What is PSNS innervation for pelvic splanchnic nerves
- Nothing to do with sympathetic trunks
- derive directly from anterior rami of spinal nerves S2-S4
- Convey presynaptic PSNS fibers to inferior hypogastric plexus
- synapse with postsynaptic neurons lying on or within abominal viscera from left colonic flexure to rectum
Where does subcostal nerve run?
T12 nerve
What nerve runs over quadratus lumborum
iliohypogastric nerve (L1)
What nerve runs along iliac crest?
ilio-inguinal nerve (L1)
What nerve runs over iliacus muscle?
Lateral cutaneous nerve of thigh (L2, L3)
WHat nerve pierces the psoas major?
Genitofemoral nerve
What nerve lies underneath psoas major?
femoral nerve (L2, L4)
Mneumonic to remember nerves of lumbar plexus?
“I Invariably Get Lazy On Fridays”
- Iliohypogastric (L1)
- ilioinguinal (L1)
- genitofemoral (L1-L2)
- lateral femoral cutaneous (L2-L3)
- obturator (L2-L4)
- femoral (L2-L4)
What forms sacral plexus?
L4-S3
- L4-S2 Common femoral/peroneal nerve
- L4-S3- contribute to tibial nerve
- Common femoral and tibial nerve form to make sciatic nerve (L4-S3)
- Largest nerve in body
- two nerves loosely bound together in same connective tissue sheath
What are the diaphragmatic apertures?
Diaphragmatic apertures
- Caval opening
- Located in central tendon
- Allows IVC and terminal branches of phrenic nerve to pass into abdominal cavity
- During inspiration, diaphragm contracts causing this opening to widen which allows for dilation of the IVC and increased blood return to the heart
- Esophageal hiatus
- Diaphragm acts as a muscular sphincter for the esophagus that constricts when diaphragm contracts
- Transmits the vagus nerve to abdominal cavity
- Aortic hiatus
- Opening posterior to the diaphragm therefore blood flow is not affected by respiration
- Transmits the descending aorta, azygos vein and thoracic duct to abdominal cavity
What is the difference between right and left domes of the diaphragm?
Right dome is slightly higher than left due to presence of liver
What is purpose of right crus from diaphragm?
Makes gastroesophageal sphincter
“ties down lower (than L), around L3 level”
wraps around esophagus
What is purpose of left crus in diaphragm?
Make aortic hiatus
What conveys motor and pain sensations from diaphragm?
phrenic nerve
Characteristics/innervation of esophagus?
- Passes into abdominal cavity via esophageal hiatus
- in muscular right crus of diaphragm
- makes inferior esophageal sphincter
- in muscular right crus of diaphragm
- Retroperitoneal organ
- Esophagogastric junction marked internally by Z-line
- transition from esophageal to gastric mucosa
- Innervation
- Vagus (PSNS)
- Greater splanchnic nerves (sympathetic)
Characteristics/innervation of stomach?
- Acidic and mechnical digestion
- can herniate through weakeneded diaphragm
- hiatal hernia
- Cardiac area
- Fundus- most superior part)
- Greater and lesser curvatures
- pylorus- (babies may have stenosis, can projectile vomit)
- internal rugae
- Innervation
- vagus (PSNS)
- Greater splanchnic nerves (sympathetic)
- T6-T9 segments which pass through celiac artery plexus
What are the parts and characteristics of the small intestine?
- Absorption of nutrients
- Duodenum
- first 10 in (25 cm), ends at duodenojejunal flexure (sharp bend)
- Jejunum (8ft)
- Ileum (11.5 ft)
- ends at ileocecal junction
- Innervation
- vagus (PSNS)
- Greater and lesser splanchnic nerves
- by way of celiac and superior mesenteric artery plexus (sympathetic
Innervation of small intestine?
- PSNS- vagus
- SNS- Greater and lesser splanchnic nerves
- by way of celiac and superior mesenteric artery plexus (sympathetic
Characteristiscs/parts of large intestine?
- Cecum
- first part, blind intestinal pouch
- appendix
- Ascending colon- retroperitoneal
- reabsorption of H2O
- Transverse colon- intraperitoneal
- Descending colon - retroperitoneal
- Sigmoid colon
- Rectum
- Anal canal
Innervation of large intestine?
- Up to left colonic flexure- vagus (PSNS)
- After left colonic flexure- sacral (S2-S4) PSNS innervation
- Ascending and transverse lumbar splanchnic nerve via superior mesenteritc ganglian (sympathetic)
- Left colonic flexure and down is lumbar splanchnic nerves via inferior mesenteric ganglion (sympathetic)
Characteristics/innervation of spleen?
- Lymphatic organ. Sits behind stomach
- Intraperiotenal
- enitrely surrounded by peritoneum except hilum area
- Innervation
- celiac artery plexus vasomotor function (sympathetic)
- vagus (PSNS)- minor action
Characteristics of pancreas?
- Behind stomach, tail of pancreas sits in spleen hilum
- Accessory digestive gland
- exocrine secretion into duodenum
- endocrine secretion into bloodstream
- Main pancreatic duct starts in pancreatic tail and joins bile duct
- empties exocrine secretions via major duodenal papilla into duodenum
- hepatopancreatic sphincter (spincter of oddi) around hepatopancreatic ampulla (ampulla of vater) prevents duodenal content form entering bile duct ampulla
Innervation of pancreas
PSNS- Vagus
Sympathetic- abdominal splanchnic nerves
Characteristics of gall bladder? Innervation?
- Concentrates and stores the bile produced by liver
- cystic duct joins up with common hepatic duct to become bile duct (which joins with main pancretic tuct)
- Innervation
- PSNS- Vagus
- SNS- Celiac nerve plexus
Characteristics of liver?
- 4 Lobes
- Right lobe (larger)
- Left lobe
- Cuadate- runs between IVC and L lobe
- Quadrate- runs between gallbladder and left lobe
- Roung ligament/ligamentum teres
- obliterated remains of umbilical vein
- well-oxygenated blood from placenta to fetus
- obliterated remains of umbilical vein
- Ligamentum venosum
- fibrous remannt of fetal ductus venosus
- shunted blood form umbilical vein to IVC- bypassing liver
- fibrous remannt of fetal ductus venosus
- Portal hepatis- contains portal vein, hepatic artery and bile ducts
What is the round ligament?
Ligamentum teres
- obliterated remains of umbilical vein
- well-oxygenated blood from placenta to fetus
What is the ligamentum venosum?
- Fibrous remnant of feta ductus venosus
- shunted blood from umbilical vein- to IVC- Bypassing liver
What forms portal hepatis?
- Portal vein–> 75-80% blood flow, 50% oxygen
-
hepatic artery–> 20-25% blood flow, 50% oxygen
- Drained by left, middle and right hepatic veins–> IVC
- common hepatic duct joins cystic duct–> bile duct
What is innervation to the liver?
- PSNS- Vagus
- SNS- Celiac artery plexus
Pathway of fetal blood?
umbilical vein (becomes ligamentum teres)–>Blood shunted away from liver in ductus venosus (becomes ligamentum venosum)–> IVC–> most blood moves RA–> LA via foramen ovale–> aorta.
Pulmonary circulation through ductus arteriosus (becomes ligamentum arteriosum) to go into aorta (most of the blood bypasses the lung in fetal circulation)
Characteristics of portal venous sytem?
- Blood leaves portal venous sytem
- in liver via hepatic veins–> IVC
- portal venous system has higher BP than IVC
- No valves
- If blood flow through portal vein becomes impaired, procedures to decrease protal HTN may be necessary (TIPS)
- hepatic artery becomes essential to maintain blood flow to liver
___ ___ ___ is hte main channel of the portal venous system.
Hepatic portal vein
- collects poorly oxygenated but nutrient rich blood from GI tract, gallbladder, pancreas and spleen
What are the various conditions that can happen when portal venous system backed up?
-
Esophageal varices- from esophageal and azygos vein (systemic system) combines with left gastric vein (portal system)
- swollen connection b/w systemic and portal systems at inferior end of esophagus
-
Hemorrhoids- from inferior an dmiddle rectal veins (systemic system) combingin with superior rectal vein (inferior mesenteric vein , portal system)
- swollen connection b/w systemic and portal systems at inferior end of rectum and anal canal
-
Caput medusae- superficial epigastric veins (systemic system) with para-umbilical veins (portal system)
- swollen connection b/w systemic and portal system around umbilicus
Characteristics of kidneys?
- Retroperitoenal, posterior abdominal wall, level of T12- L3- left higher than right
- Renal hilum
- renal sinus
- Renal artery (superior), renal vein (inferior), renal pelvis
Innervation of kidney?
- PSNS- Vagus
- SNS- Abominal pelvic splanchnic nerves (Greater, lesser, and least) via celiac and superior mesenteric ganglion
What do the ureters overlie?
innervation?
- Ureters pass over bifurcation of common iliac arteries to urinary bladder
- PSNS- Vagus and sacral parasympathetic division
- SNS- Splanchnic nerves via inferior mesenteric ganglion
Characteristics of suprarenal gland?
- Superomedial aspect of each kidney
- Endocrine system
- secrete corticosteroids, androgens, epi and NE
- Receives a great amount of blood supply
- suprarenal arteries (direct branch from aorta)
- inferior phrenic artery
- renal arteries
Innervation for suprarenal gland?
- Abdominopelvic (greater, lesser and least) splanchnic nerves via celieac arteyr plexus
- myelinated presynaptic sympathetic fibers from intermediolateral horn of spinal cord and transverse the paravertebral ganglia without synapse
- synapse directly within the adrenal gland- acts as postsynaptic neuron
Where does abominal aorta lie? Branches?
- Begins at hiatus (T12), end at bifurcation (L4) of L and R common iliac artery
-
4pairs of lumbar arteries
- supply lumbar vertebrae, back muscles, posterior abdominal wall
- Inferior phrenic arteries (paired)–> suprarenal gland, diaphragm
- Suprarenal arteries (paired)–> suprarenal gland
- celiac trunk (unpaired) **
- renal arteries (paired)–> kidney
- Superior mesenteric artery (unpaired)**
- Gonadal (ovarian or testicular arteries (paired)–> ovaries or testes
- Inferior mesenteric artery (unpaired) **
- Median sacral artery–> rectum
Divison of common iliac arteries?
- Internal iliac arteries enter pelvis
- External iliac arteries–> femoral artery at inguinal ligament
- inferior epigastric artery and deep iliac circumflex arteries
3 arteries we need to know for visceral arterial supply?
- Celiac trunk
- Superior mesenteric artery
- inferior mesenteric artery
To what does the celiac trunk supply blood?
- liver
- stomach
- duodenum
- pancreas
- spleen
(this is same as sympathetic innervation because sympathetic fibers for these organs follow celiac artery plexus)
To which organs does the superior mesenteric supply blood?
- Pancreas
- duodenum
- jejunum
- ileum
The superior mesenteric branches into middle and right colonic arteries
- supply blood up until the left colonic flexure
Where does the inferior mesenteric artery supply blood?
- Left colonic arteries from left colonic flexure to rectum
Where does superior mesenteric artery cross by?
in notch of pancreas, near bend of duodenum
When would your acending colon be necrotic, but transverse colon receive blood flow?
Clt in Right colonic artery, or in SMA BELOW the middle colonic artery
Middle colonic artery branches off SMA BEFORE the right colonic artery
If you have blood clot at origin of SMA, what can happen?
Entire ascending, transverse colon ischemic
Characteristics of IVC?
- Receives poorly oxygenated blood from lower limbs, most of back, abdominal walls and abdominopelvic viscera (via portal system)
- Begins at L5 with union of common iliac veins
- external and internal iliac veins
- Right to aorta
- leaves abdominal cavity via caval opening in diaphragm
Tributaries of the posterior wall venous system?
- Tributaries to IVC correspond to branches of aorta
- Lumbar veins
- right gonadal vein (testicular or ovarian)
- left drains into left renal vein
- Right and left renal veins
- right suprarenal vein
- left drains into left renal vein
- hepatic veins from liver
What might a tumor in head of pancreas cause?
decrease blood flow back to IVC
What might a tumor in the body of the pancreas cause?
Decrease blood flow through SMA
Which vein is longer, left or right renal?
Left renal because it has to transverse the aorta