Module 2: The Abdomen Flashcards
4 quadrants of the abdomen
Left and right upper and lower
9 divisions of the anterior abdominal wall
- Epigastric
- Umbilical
- Hypogastric
- Left hypochondriac
- Left lumbar
- Left inguinal
- Right hypochondriac
- Right lumbar
- Right inguinal
Layers of the abdominal wall (superficial to deep)
- Skin
- Superficial fascia
- Investing fascia
- External oblique
- Internal oblique
- Transervsalis abdominus
- Extraperiotoneal fat
- Transversalis fascia
- Parietal peritoneum
What is a liposuction?
Surgical suctioning of fat deposits of the body, involves the removal of the superficial facia layer (Camper’s fascia)
Superficial fascia layer divisions
Camper’s fascia (superficial)
Scarpa’s fascia (membranous)
Symptoms of potential liposuction complications
Bruising, swelling, damage to other layers of abdominal wall
What is the rectus sheath?
Protective layer within the anterior abdominal wall that supports and protects the contents of the abdomen
What is the rectus sheath made up of?
The aponeurotic internal oblique, external oblique and transversus abdominus
What is an aponeurosis?
Flat-sheet of tendon like material that anchors a muscle or connects it w the part that the muscle moves
What is rectus abdominus diastasis?
Condition in which the rectus abdominus muscles become separated due to a thinning and widening of the linea alba
Symptoms of rectus abdominus diastasis
Protruding midline and lower back pain
Blood supply to the anterior abdominal wall
- Superior epigastric artery
- Inferior epigastric artery
Superior epigastric artery
Terminal branch of the internal thoracic artery
Enters rectus sheath posteriorly and anastomoses w the inferior epigastric artery
Inferior epigastric artery
Branch of external iliac artery
What is a rectus sheath hematoma?
Result of bleeding of the rectus sheath from damage to the superior and/or inferior epigastric arteries and their branches which could happen from a direct tear of rectus sheath or abdominal muscles
Symptoms of rectus sheath hematoma
Blood collects on anterior abdominal wall causing bruising, tenderness, pain and bulging of abdomen
Lymphatic drainage of anterior abdominal wall
- Superficial
- Deep
Superficial lymphatic drainage
Drainage to axillary nodes from above the umbilicus to the superficial inguinal nodes below the umbilicus
Deep lymphatic drainage
Drainage to external iliac, common iliac and lumbar nodes
Inguinal canal
4-6cm in length located in lower anterior abdominal wall
Imp passageway for structures btwn abdominal and pelvic region
Inguinal rings
Ends of the inguinal canal, act at doorways for contents to enter and exit
Superficial inguinal ring
Opening in external oblique aponeurosis, superior to pubic tubercle
Deep inguinal ring
Invagination of transversals fascia, superior to midpoint of inguinal ligament
Contents of inguinal canal in females
Main structure is the round ligament of uterus
Innervation of inguinal canal in females
Ilioinguinal nerve supplies skin of upper labia majora and mons pubis
Contents of inguinal canal in males
Main structure is spermatic cord
Innervation of inguinal canal in males
Ilioinguinal nerve supplies skin of upper scrotum and root of penis
Ilioinguinal nerve
Passes through canal and exits through superficial inguinal ring; supplies skin of adjacent upper thigh in both males and females
What is an inguinal hernia?
When contents of the abdominal cavity protrude into the inguinal canal; happens at weak spots of abdominal wall
Weak spots of female abdominal wall
Where round ligaments of uterus attaches to the tissue surrounding the pubic bone
Weak spots of male abdominal wall
In inguinal canal where spermatic cord enters the scrotum
Symptoms of inguinal hernia
Bruising, bulging, pain especially when bending over, lifting objects or coughing
What causes weakness in abdominal wall?
Giving birth, injury, aging
Major muscles of the posterior abdominal wall
Divided into superior and inferior portions
What borders the posterior abdominal wall superiorly?
The diaphragm
Major muscles of posterior abdominal wall (superior)
Larger right and smaller left crus of diaphragm
Right cura origin
L1-L3
Left cura origin
L1-L2
Major muscles of posterior abdominal wall (inferior)
Psoas major
Illiacus
Quadratus lumborum
Iliopsoas muscle
Formed by the merging of the psoas major and iliacus and inserts onto the lesser trochanter of the femur
Quadratus lumborum
Thin, flat muscle that originates on iliac crest and lumbar vertebrae and inserts into rib 12
Tight Quadratus Lumborum
Tight muscles on one side of posterior abdominal wall can lift the corresponding side of one’s pelvis leading to a misalignment and can pull at the ribs limiting reaching and breathing
What happens if both quadratus lumborum muscles are tight?
Compression on spine and back pain
Formation of lumbar plexus
Formed in psoas major muscle from the ventral (anterior) rami of lumbar spinal nerves 1-4
Nerves of the lumbar plexus
- Iliohypogastric
- Ilioinguinal
- Genitofermoral
- Lateral femoral cutaneous
- Femoral
- Obturator
- Lumbosacral trunk
Iliohypogastric nerve
Spinal nerve L1
Supplies skin and muscles of lower abdominal wall
Ilioinguinal nerve
Spinal nerve L1
Runs through inguinal canal, supplies skin of upper medial thigh, root of penis and anterior scrotum in males and skin of mons pubis and labium majora in females
Genitofemoral nerve
Spinal nerves L1 and L2
Two branches: genital and femoral
Genital branch
Enters inguinal canal
Femoral branch
Supplies skin of upper anterior thigh
Lateral femoral cutaneous nerve
Spinal nerves L2 and L3
Supplies skin of anterolateral thigh
Femoral nerve
Spinal nerves L2-L4
Supplies muscles of anterior compartment of thigh, hip and knee joints and skin of anterior thigh
Obturator nerve
Spinal nerves L2-L4
Supplies muscles of medial compartment of thigh, hip and knee joints and skin of medial thigh
Lumbosacral trunk
Part of L4 that joins L5
Joins S1-S4 ventral rami to form the sacral plexus
What is a femoral nerve entrapment?
Pinching of femoral nerve
What causes femoral nerve entrapment?
Disc herniation at vertebral level L2/3 or L3/4
Bulging disc impinges femoral nerve
Symptoms of femoral nerve entrapment
Pain, numbness, weakness along front thigh
Sympathetic nerves of posterior abdominal wall
Lumbar sympathetic trunk
Lumbar sympathetic trunk
Runs down posterior abdominal wall lateral to vertebral column
Parasympathetic nerves of posterior abdominal wall
Vagal trunks
Pelvic splanchnic nerves
Vagal trunks
Branches of left and right vagus nerves that carry parasympathetic fibres to the aortic plexus
Pelvic splanchnic nerves
Spinal nerves S2-S4
Carry parasympathetic fibres to the superior hypogastric plexus
The autonomic plexuses (that we focus on)
Aortic (prevertebral) plexus
Superior hypogastric plexus
Aortic plexus
Includes prevertebral ganglia
Innervates organs of abdomen such as stomach, small and large intestine and kidneys
Prevertebral ganglia
Celiac
Superior mesenteric
Inferior mesenteric
Aorticorenal
Superior hypogastric plexus
At bifurcation of descending aorta
Innervates organs of pelvis such as uterus, prostate, bladder, rectum and perineum
What is diabetic gastroparesis?
Impaired innervation to abdominal viscera that can result in dysmotility (disordered peristalsis)
Symptoms of diabetic gastroparesis
Bloating, abdominal pain, nausea and vomiting
NO structural abnormalities in gut and NO inflammation
Bifurcations of the abdominal aorta
Bifurcates at L4/L5 into left and right common iliac arteries which bifurcate into external and internal iliac arteries
What causes an aortic dissection (tear)?
Trauma to abdominal region
Hypertension bc walls of blood vessels are weakened over time
Symptoms of aortic dissection
Abdominal pain, weakness, fainting due to blood loss
Anterior unpaired visceral branches of the abdominal aorta
- Celiac artery
- Superior mesenteric artery
- Inferior mesenteric artery
Celiac artery
Forms at T12 and has three branches Supplies foregut structures
Three branches of celiac artery
Left gastric, common hepatic and splenic arteries
Foregut structures
Distal esophagus to proximal duodenum
Includes pancreas, liver, gallbladder
Superior mesenteric artery
Forms at L1 and supplies midgut structures
Branches of superior mesenteric artery
Inferior pancreaticoduodenal artery
Jejunal and ileal arteries
Middle and right colic arteries
Midgut structures
Extend from distal duodenum to proximal half of transverse colon
Inferior mesenteric artery
Forms at L3 and has three main branches
Supplies hindgut structures
Branches of inferior mesenteric artery
Left colic, sigmoidal and superior rectal arteries
Hindgut structures
Distal third of transverse colon to rectum
Lateral paired visceral branches
- Suprarenal arteries
- Renal arteries
- Gonadal arteries
Suprarenal arteries
Formed at L1
Renal arteries
Formed btwn L1 and L2
Gonadal arteries
Formed at L2
Posterior parietal branches
Supply structures of posterior abdominal wall
1. Right and left inferior phrenic arteries
2. Lumbar arteries
Inferior phrenic arteries
Arise below aortic hiatus near beginning of abdominal aorta and supply inferior surface of diaphragm
Lumbar arteries
4 pairs; run in series w intercistal arteries and supply posterior abdominal wall
What is splenic artery infarction?
Condition in which splenic artery is obstructed/blocked resulting in decreased blood flow to spleen
Symptoms of splenic artery infarction
Slow developing pain in upper left quadrant of abdomen
Tributaries of inferior vena cava
Right and left renal veins
Hepatic veins
Inferior phrenic
Lumbar veins
Left suprarenal
Right gonadal veins
What causes inferior vena cava syndrome?
Obstruction of the IVC due to compression or infarction of its major tributaries
Symptoms of IVC syndrome?
Edema (swelling) below diaphragm, especially lower limbs
What is the peritoneum?
Serous membrane that helps support organs in the abdominal cavity and allows passage of nerves, blood and lymph vessels to organs
Layers of the peritoneum
Parietal and visceral
Parietal peritoneum
Lines inferior surface of diasphragm, the abdominal and pelvic walls and forms a roof over pelvic viscera
Visceral peritoneum
Covers organs so that when their visceral surfaces are in contact w each other or w the parietal peritoneum the serous fluid allows free movement
Peritonitis
Inflammation of the peritoneum caused by bacterial infection
Symptoms of peritonitis
Abdominal pain, weight loss, tenderness of abdomen
Peritoneum in females
Incomplete closure of the peritoneal cavity to allow for communication w the exterior openings of the fallopian tubes
**can lead to spread of infection such as yeast
Peritoneum in males
Closed sac
Peritoneal folds
Greater and lesser omenta
Mesentaries
Omenta
Large doubles of folds consisting greater and lesser portions
Cushions the intestines and act as a protective barrier for infection and trauma
Greater omentum
Below stomach
Lesser omentum
Btwn stomach and liver
Mesentaries
Double folds that anchor the abdominal organs to posterior abdominal wall
Intraperitoneal organs
Almost completely covered by peritoneum and reside within peritoneal cavity
Anchored to posterior abdominal wall by mesentary
What are the intraperitoneal organs?
SALTED SPRSS
-stomach
-appendix
-liver
-transverse colon
-duodenum(1st part)
-small intestine(jejunum and ileum)
-pancreas(tail)
-rectum(upper third)
-spleen
-sigmoid colon
Retroperitoneal organs
Behind peritoneum, only covered anteriorly
What are the retroperitoneal organs?
SAD PUCKER
-suprarenal glands
-aorta/IVC
-duodenum(2nd-4th parts)
-pancreas
-ureters
-colon(ascending and descending)
-kidneys
-esophagus
-rectum
Peritoneal cavity
Space btwn parietal and visceral layers of peritoneum
Lesser peritoneal sac (omental bursa)
Lies behind stomach and extends upward to diaphragm (superior recess)
Extends downward btwn layers of greater omentum (inferior recess)
Extends left to spleen and right to communicate w greater sac
How does the lesser sac communicate w the greater peritoneal sac?
Through the epiglotic (omental) foramen (of Winslow)
Innervation of parietal peritoneum
Network of nerves including phrenic and lower intercostal nerves
Pain and parietal peritoneum
Well-localized sensitivity to pain bc it receives same somatic nerve supply as the region of abdominal wall that it lines
Innervation to visceral peritoneum
Supplied by visceral sensory nerves that accompany autonomic nerves
Pain and visceral peritoneum
Poorly localized
Lymphatics of posterior abdominal wall
Pre aortic lymph nodes
Para-aortic lumph nodes (lumbar)
Where do pre-aortic lymph nodes drain?
Drain lymph from foregut, midgut and hindgut structures
Where are pre-aortic lymph nodes located?
Anterior surface of aorta in close proximity to major unpaired branches of aorta
Where do para-aortic lymph nodes drain?
Drain lymph from posterior abdominal wall, kidneys, suprarenal gland, ureters, gonads, uterus and uterine tubes
Where are para-aortic lymph nodes located?
Along length of aorta on right and left sides
What is reactive lymphadenopathy?
Occurs when lymph nodes become swollen due to an immune response from lymphocytes
Symptoms of reactive lymphodenapathy
Tenderness, pain, warm upon touch in area of affected lymph nodes
Parts of the esophagus
- Cervical
- Thoracic
- Abdominal
Abdominal esophagus
1-2.5cm
Begins at esophageal hiatus and terminates at stomach, inferior to diaphragm
Thoracic esophagus
Lungs are lateral to it
Posterior to trachea
The lower esophageal sphincter (LES)
Prevents reflux of gastric contents into esophagus via involuntary control
Gastroesophageal reflex (GERD)
Weak or abnormal closure of LES resulting in regurgitation of stomach contents into esophagus causing a burning sensation felt as heartburn
Symptoms of GERD
Chest pain (near thoracic esophagus T8), nausea, vomiting of refluxed content
Pyloric orfice
Narrowing of stomach walls at distal end where stomach contents are emptied into small intestine
Pyloric sphincter
Controls movement of content from stomach into duodenum (autonomic control)
Gastroparesis
Results if pyloric sphincter doesn’t open completely or at the right time causing a delay of emptying
Endoscopy
Insertion of a long tube into body to observe an internal organ in detail
Blood supply of stomach
Right and left gastric arteries–> anastomose at lesser curvature
Right and left gastro-epiploic arteries –> anastomose at greater curvature
Small intestine
Extends from pyloric orfice to ileocecal junction
3 parts: duodenum, jejunum, ileum
Parts of the duodenum
- Superior part
- Descending part
- Horizontal part
- Ascending part
Superior part of duodenum
Only part of duodenum that is intraperitoneal
Bile duct and gastroduodenal artery pass posterior to it
Descending part of duodenum
Anterior to hilum of kidney
Contains major duodenal papilla
Major duodenal papilla
Site where the hepatopancreatic ampulla (of Vater) drains into duodenum
Hepatopancreatic ampulla
Union of common bile duct and pancreatic duct
Horizontal part of duodenum
Passes across IVC and abdominal aorta, inferior to origin of SMA and vein
Superior mesenteric artery syndrome
Compression of duodenum btwn aorta and SMA
Ascending part of duodenum
Up and left of aorta, forming duodenojejunal flexure
How is the duodenojejunal flexure anchored to posterior abdominal wall?
Ligament of Treitz
Blood supply to foregut portion of duodenum (first and second parts)
Gastroduodenal artery and its branch (superior pacreaticoduodenal artery)
Blood supply to midgut portions of duodenum (third and fourth parts)
Inferior pancreaticoduodenal artery (branch of SMA)
Blood supply of jejunum and ileum
Jejunal and ileal arteries (arcades and vasa recta)
Networks that supply jejunum
Fewer arcades with long vasa recta
Networks that supply ileum
Many arcades with short vasa recta
Meckel’s diverticulum
Birth defect resulting in an outpouching of tissue in distal ileum
Symptoms of Meckel’s diverticulum
May become ulcerated resulting in blood in stool, intestinal obstruction resulting in vomiting and constipation, pain in epigastric and umbilical regions
Complication with Meckels diverticulum
Pain is confused w pain from appendicitis
Three distinguishing features of large intestine
- Teniae coli
- Haustra
- Epiploic (omental) appendages
Teniae coli
3 thickened bands of longitudinal muscle
Haustra
Segmented folds or pouches
Epiploic appendages
Fatty tags closed by peritoneum
Hirschsprung disease
Disorder that occurs at birth when motor nerve cells (auerbach’s plexus) are absent in the muscles of the colon making it difficult to pass stool
Cecum
Where ileum joins large intestine in right inguinal region
Ileocecal valve
Controls opening of ileum into cecum
Intraperitoneal parts of large intestine
Cecum, transverse colon, sigmoid colon
Retroperitoneal parts of large intestine
Ascending and descending colon, rectum
Blood supply of midgut portion of large intestine
Ileocolic artery (cecum and appendix)
Right colic artery (ascending colon)
Middle colic artery (transverse colon)
Blood supply of hindgut portion of large intestine
Branches of inferior mesenteric artery
Blood supply of descending colon
Left colic artery
Blood supply of sigmoid colon
Sigmoidal arteries
Blood supply of rectum and upper anal canal
Superior rectal artery
Marginal artery
Formed by anastomoses btwn right, middle and left colic arteries, provides collateral circulation
Mesenteric artery ischemia
Occlusion of mesenteric arteries causing reduced blood flow to structures of midgut (distal duodenum, jejunum, ileum and colon) and tissue death
Symptoms of mesenteric artery ischemia
Disrupted bowel movements, nausea, vomiting, abrupt abdominal pain accompanied by abdominal tenderness
Venous drainage of gastrointestinal viscera
- Splenic vein
- Superior mesenteric vein
- Inferior mesenteric vein
**all drain into hepatic portal vein
Where does the splenic vein travel?
Leaves spleen and passes posterior to pancreas to join superior mesenteric vein
What does the splenic vein drain?
Spleen, lower esophagus, part of stomach and pancreas
Thrombosis
Formation of blood clot
Pancreatic conditions can compress splenic vein and lead to this
Superior mesenteric vein
Ascends through mesentery of small intestine to join splenic vein posterior to pancreas
Mesenteric ischemia
Occlusion of superior and/or inferior mesenteric vein
Inferior mesenteric vein
Ascends on left to join splenic vein
Hepatic portal vein
Carries nutrient rich deoxygenated blood from digestive tract to liver
What forms the hepatic portal vein?
Union of splenic and superior mesenteric veins posterior to pancreas
Liver
Largest internal organ in body
Lobes separated by falciform ligament
Subphrenic recess
Superior extensions of peritoneal cavity btwn liver and diaphragm
Hepatorenal recess (pouch of Morrison)
Deep recess in peritoneal cavity on right side btwn liver and right kidney
Blood supply of liver
1/3 of cardiac output passes through liver; 80% is delivered via portal vein and 20% delivered via hepatic artery proper
Portal vein thrombosis
Blood clot forms in portal vein, interrupting the flow of nutrient rich blood from the intestines to liver
Symptoms of portal vein thrombosis
Upper right abdominal pain, abdominal swelling and fever
The gallbladder
Receives, concentrates and stores bile
Fundus, body, neck
Gallstones
Hardened deposits of bile that form in gallbladder
Typically asymptomatic and only cause pain when they obstruct biliary duct
Biliary colic
Spasmodic pain caused by an attempt to expel a gallstone
What structures are affected if a gallstone blocks common bile duct?
Liver, gallbladder, pancreas
Cholangitis
Inflammatory condition of biliary duct system caused by gallstones blocking a duct
How does cholangitis affect the blood stream?
Due to presence of gallstones, bacteria enters biliary tree by reverse ascent from duodenum causing a block in passageway and infection
Increased biliary pressure spreads infection into hepatic veins leading to bacteremia (bacteria in bloodstream)
Symptoms of cholangitis
Pain in upper right quadrant of abdomen, fever, chills, nausea, vomiting
Location of head of pancreas
In concavity of duodenum on right side of abdominal cavity; has a medial projection (uncinate process)
Location of body of pancreas
Extends left behind stomach
Tail of pancreas
Abuts medial side of spleen
Pancreatitis
Inflammation of pancreas, can be caused by gallstones
How does pancreatitis occur from gallstones?
if gallstones block common bile duct, pancreatic enzymes are blocked from passing into the small intestine forcing them into the pancreas; recycled enzymes irritate cells of pancreas causing inflammation
Symptoms of pancreatitis
Upper abdominal pain, upper left quadrant pain, nausea/vomiting, fever
The spleen
Largest lymphatic organ in body, located in upper left quadrant of abdomen
Splenomegaly
Condition that occurs when spleen becomes enlarged and compresses the duodenum btwn the aorta and SMA
Symptoms of splenomegaly
Pain in left upper abdomen, jaundice
The kidneys
Retroperitoneal structures on posterior abdominal walls
**right kidney slightly lower due to liver above it
Pyelonephritis
Kidney infection caused by bacterial infection of liver
Symptoms of pyelonephritis
Flank pain and fever
What is flank pain?
Discomfort in upper abdomen or back and sides
Ureters
Muscular tubes that transport urine from kidneys to bladder
Left ureter slightly longer
Ureter stones
Kidney stone that has moved to ureters, blocking pathway of urine from kidney to bladder
Symptoms of ureter stone
Severe, intermittent pain in flank region, blood in urine, fever, nausea, vomiting
Adrenal (suprarenal) glands
Right adrenal gland- pyramidal
Left adrenal gland- semilunar
Blood supply of adrenal glands
Suprarenal artery and branches from inferior phrenic and renal arteries
Adrenal gland tumour symptoms
Results in superior pain, imbalance/overproduction of hormones leading to excessive hair growth and unusual acne
Blood supply to kidneys (arteries)
Left and right renal arteries that arise from lateral side of abdominal aorta at L2
Accessory renal arteries
Blood supply to kidneys (veins)
Left and right renal veins travel anterior to renal arteries
Left renal vein passes under SMA to drain into IVC; longer bc it has to cross aorta
Nutcracker syndrome
Rare condition that occurs when left renal vein becomes compressed btwn abdominal aorta and SMA
Symptoms of nutcracker syndrome
Pressure increase in renal vein leading to blood and protein in urine, flank pain and abdominal pain
Pyelonephritis
Severe UTI which manifests suddenly; bacteria from bladder migrates to kidney
Thoracic/descending aorta blood supply
Bronchial arteries, mediastinal arteries and pericardial arteries
Posterior intercostal artery
