Abdomen Flashcards
Abdominal boundaries
Superior: Diaphragm
Inferior: Pelvis
Posterior: Vertebral column and posterior and inferior ribs
Lateral: Muscles of the flank
Anterior: Abdominal muscles
Three distinct spaces in the abdomen
- Peritoneal Space -
Organs covered by abdominal (peritoneal) lining - Retroperitoneal Space
Organs posterior to the peritoneal lining ***most damage occurs - Pelvic Space
Organs contained within pelvis
Structure of abdominal cavity
Superiorly it is formed by diaphragm which separates the abdominal cavity from the thoracic cavity
Inferiorly the abdominal cavity is continuous with the pelvic cavity through the pelvic inlet
Structure of abdominal wall
Anteriorly:
The abdominal wall is formed above by lower part of the thoracic cage
Below by the rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles and fasciae
Structure of anterior abdominal wall
It is made up of skin, superficial fascia, deep fascia, muscles, extraperitoneal fascia and parietal peritoneum
The abdominal walls are lined by a fascial envelope and the parietal peritoneum
Muscles of the abdominal wall
- Rectus abdominus
2.External Obliques - Internal Obliques
- Transverse Abdominus
Rectus Abdominis - Origin and insertion
Inferiorly - attached by two tendons;the larger one is attached to the pubic crest, from the pubic tubercle to the pectineal line, while the small, medial tendon is attached to the pubic symphysis
Origin- Pubic symphysis, pubic crest
Insertion- Xiphoid process of sternumandcostal cartilages of the 5th, 6th and 7th ribs
Rectus Abdominis - Blood Supply
Inferior and superior epigastric arteries
Rectus Abdominis Innervation
Innervated by the thoracoabdominal nerves, which enter the rectus sheath by piercing its anterior surface.
They pass between the transversus abdominis and internal oblique muscle layer and pierce the sheath of the rectus abdominis muscle.
The nerves are simply the anterior divisions of the 7th to 11th lower intercostal nerves, that continue to supply the abdominal wall after the intercostal spaces they supplied end medially.
External Oblique - Origin, insertion, action
Origin:(proximal attachments) External surfaces of ribs 5-12.
Insertion:(distal attachments) Anterior iliac crest and abdominal aponeurosis to Linea alba.
Action:
Flexes the Vertebral Column (draws Thorax downward)
Rotates the Vertebral Column
Laterally Flexes the Vertebral
Column`
Internal Oblique - origin /insertion
Origin: (proximal attachments)
Anterior iliac crest, lateral half of inguinal ligament, and thoracolumbar fascia.
Insertion: (distal attachments)
Costal cartilages of ribs 8-12; abdominal aponeurosis to Linea alba.
Transverse Abdominis origin
The transversus abdominis originates from multiple locations in the body, which include:
Costal margin: inner surface of costal cartilage and ribs 7-12.
Thoracolumbar fascia: large, diamond-shaped sheet of connective tissue located at the lower back
Front two-thirds of iliac crest: top border of the pelvic bone. Outer third of the inguinal ligament: a band of connective tissue the extends diagonally down the front of the pelvis
Transverse abdominis Insertion
Linea alba: fibrous band of connect tissue that runs down the front of the abdominal wall
Pubic symphysis: connective tissue that joins the left and right sides of the lower, front pubic bone
Xiphoid process: hardened cartilage that extends off the bottom of the sternum (i.e. breast plate)
Transverse Abdominis Innervation
The transversus abdominis is innervated by several nerves, which include:
Lower five intercostal nerves:
The intercostal nerves are a collection of nerves that originate from the spinal cord in the first eleven thoracic vertebrae (T1-T11). The transversus abdominis is innervated by the lower five of these intercostal nerves (T7-T11).
Subcostal nerve: A nerve that originates from the spinal cord in the bottom thoracic vertebrae (T12).
Iliohypogastric nerve: A branch of the lumbar plexus, which is a network of nerves in the lower back. Nerve fibers of the iliohypogastric nerve originate from the L1 section of the spinal cord.
Ilioinguinal nerve: Another branch of the lumbar plexus that also originates from the L1 section of the spinal cord.
Blood supply of the abdominal skin areas
Skin near the midline is supplied by branches of the superior epigastric artery (br. of int. thoracic artery) and the inferior epigastric artery ( br. of external iliac artery)
Skin of the flanks is supplied by branches from the intercostal, lumbar, and deep circumflex arteries
Abdominal Venous Drainage
Venous blood is collected into a network of veins that radiate from the umbilicus
The network is drained above into the axillary vein via the lateral thoracic vein
Below into the femoral vein via the superficial epigastric and the great saphenous veins
Few small veins, the paraumbilical veins form a clinically important portal-system venous anastomosis.
Caput Medusae
The superficial veins around the umbilicus and the paraumbilical veins connecting them to the portal vein may become grossly distended in case of portal vein obstruction
The distended subcutaneous veins radiate out from the umbilicus, producing in severe cases the clinical picture called Caput Medusae.
** Can be liver issue, alcoholism,
liver tumor, cancer metastasizing and backing up into the venus system
Nerves of the anterior abdominal wall
supply the skin, muscles and the parietal peritoneum
They are derived from the anterior rami of lower six thoracic and the first lumbar nerves
Inflammation of parietal peritoneum causes pain in the overlying skin and also a reflex increase in tone of the abdominal musculature in the same area
Lymph drainage of the skin of the anterior abdominal wall
above the umbilicus is upward to the anterior axillary (pectoral group of nodes)
Below the level of umbilicus drains downward and laterally to the superficial inguinal nodes
Swelling in the groin is may be due to enlarged superficial inguinal node
Rectus Sheath- general
Is a long fibrous sheath
Encloses the rectus abdominis and pyramidalis muscle (if present)
Contains the anterior rami of lower six thoracic nerves and the superior and inferior epigastric vessels and lymph vessels
Formed mainly by aponeurosis of three lateral abdominal muscles
Three levels of the Rectus Sheath
- Above the costal margin the anterior wall is formed by the aponeurosis of the external oblique and posterior wall is formed by the thoracic wall
That is the 5th , 6th and 7th costal cartilages and the intercostal spaces
- Between the costal margin and the level of the anterosuperior iliac spine, the aponeurosis of the internal oblique splits to enclose the rectus muscle
The external oblique aponeurosis is directed in front of the muscle
Transversus aponeurosis is directed behind the muscle
- The posterior wall of the rectus sheath is not attached to the rectus abdominis muscle
The anterior wall is firmly attached to it by the muscle’s tendinous intersections
Digestive Tract Anatomy
- Esophagus:
Carries food/liquid to stomach - Small intestine:
Duodenum, jejunum, ileum - Large intestine:
Cecum, ascending colon, transverse colon, descending colon, sigmoid colon
3.Rectum and Anus
Retroperitoneal Structures
- Kidneys
- Adrenals
- Pancreas
- abdominal aorta
- IVC
- Nerve roots and lymph nodes
Visceral Pain
Stretching of hollow viscus or capsule of solid viscus
Visceral fibers enter the spinal cord at several levels leading to poorly localized, poorly characterized pain. (dull, cramping, aching).
Visceral pain approx. locations
Visceral pain can be localized by the sensory cortex to an approximate spinal cord level determined by the embryologic origin of the organ involved.
Foregut organs (stomach, duodenum, biliary tract) produce pain in the epigastric region
Midgut organs (most small bowel, appendix, cecum) cause periumbilical pain
Hindgut organs (most of colon, including sigmoid) as well as the intraperitoneal portions of the genitourinary tract cause pain initially in the suprapubic or hypogastric area.
Parietal Pain
Parietal abdominal pain is caused by irritation of fibers that innervate the parietal peritoneum
Parietal pain, in contrast to visceral pain, can be localized to the dermatome superficial to the site of the painful stimulus.
As the underlying disease process evolves, the symptoms of visceral pain give way to the signs of parietal pain, causing tenderness and guarding. As localized peritonitis develops further, rigidity and rebound appear.
Referred Pain
Pain or discomfort that is perceived at a site distant from the affected organ because of overlapping transmission pathways
Also reflects embryologic origin:
subdiaphragmatic irritation -> ipsilateral supraclavicular or shoulder pain gynecologic pathology -> back or proximal lower extremity painbiliary tract disease -> right infrascapular painmyocardial ischemia ->midepigastric, neck, jaw, or upper extremity painureteral obstruction -> ipsilateral testicular pain
Hernia + Three Types
Hernia is derived from the Latin for “rupture. “ It is the protrusion of an organ or part of an organ through a defect in the wall of the cavity normally containing it.
- Reducible, Hernias can be reducible if the hernia can be easily manipulated back into place.
- Irreducible or incarcerated, this cannot usually be reduced manually because adhesions form in the hernia sac.
- Strangulated, if part of the herniated intestine becomes twisted or edematous and causing serious complications, possibly resulting in intestinal obstruction and necrosis.
Femoral Herniation
through the femoral canal
Inguinal Hernias
Inguinal hernia results because pressure finds weak spot at inguinal canal.
Groin hernias are found in 5% of male population.
Represents 86% of all hernia cases. It occurs 5 times more often in males than females.
Inguinal 96% ( indirect 75%, direct 25%). Bilateral in 20% of cases
Right sided hernias are more frequent than left sided ones
Femoral 4%.
Direct Inguinal Hernia
Incidence: 25% of hernia cases
The hernia contents enter the inguinal canal.
These hernias are generally considered to be acquired, and may be associated with heavy lifting, straining due to constipation, coughing, or prostatic enlargement.
Bilateral Hernia
Simultaneous Right and Left Inguinal Hernia.
Common in children and elderly men
If a left inguinal hernia is present, there is a 25% risk of an occult right inguinal hernia.
Incisional Hernia
Pathophysiology-
Type of Ventral Hernia, develops in scar of prior laparotomy or drain site.
Risks for postoperative hernia development
- Vertical scar more commonly affected than horizontal
- Wound infection
- Wound dehiscence
- Malnutrition
- Obesity
- Tobacco abuse
Bowel Incarceration
The trapping of abdominal contents within the Hernia itself
Hernia Strangulation
- Pressure on the hernial contents may compromise blood supply (especially veins, with their low pressure, are sensitive, and venous congestion often results) and cause ischemia, and later necrosis and gangrene, which may become fatal.
Small Bowel Obstruction
Partial or complete blocking of the small bowel.
The cystic artery which supplies the gallbladder is usually a branch of what artery?
The Right Hepatic Artery
(90% of the time)
Gall Bladder anatomy
- Pear-shaped, hollow, saclike organ.
7.5 – 10 cm long. - Lies in a shallow depression on the inferior surface of the liver attached by loose connective tissue.
- Capacity - 30 – 50ml of bile.
- Gallbladder wall smooth muscle.
Connected to CBD by cystic duct.
Bile, amount, appearance and components
Digestive juice made by the liver.
aids in digesting fats and fatty foods in our diet.
Normal golden color.
¼ - 1¼ Liters of bile each day.
Water
1. Electrolytes: Na, K, Ca, Cl, HCO3
2.Fatty acids
3. Cholesterol
3. Billirubin
4. Bile salts
Blood supply for the gall bladder
Cystic Artery (RHA)
Murphy’s sign
is RUQ pain upon palpation which causes a cessation of breathing.
Sequence of RUQ imaging
Ultrasound – 1st
CT / HIDA – 2nd
ERCP / MRCP– 3rd
Symptomatic cholelithiasis
Wax/waning postprandial epigastric/RUQ pain due to transient cystic duct obstruction by stone, no fever/WBC, normal Liver Function Test.
Acute cholecystitis
Acute GB inflammation due to cystic duct obstruction. Persistent RUQ pain +/- fever, ↑WBC, ↑LFT, +Murphy’s = inspiratory arrest
Chronic cholecystitis
Recurrent bouts of colic/acute chol’y leading to chronic GB wall inflamm/fibrosis. No fever/WBC.
Acalculous cholecystitis
GB inflammation due to biliary stasis(5% of time) and not stones(95%). Seen in critically ill pts
Choledocho-lithiasis
Gallstone in the common bile duct (primary means originated there, secondary = from GB)
Cholangitis
Infection within bile ducts due to obstrux of CBD.
(Charcot triad): RUQ pain, jaundice, fever (seen in 70% of pts), can lead to septic shock.
Symptomatic cholelithiasis
“biliary colic”
The pain occurs due to a stone obstructing the cystic duct, causing wall tension; pain resolves when stone passes
Pain usually lasts 1-5 hrs, rarely > 24hrs. Ultrasound reveals evidence at the crime scene of the likely etiology: gallstones
Chronic calculous cholecystitis
Recurrent inflammatory process due to recurrent cystic duct obstruction, 90% of the time due to gallstones
Overtime, leads to scarring/wall thickening.
Treatment: laparoscopic cholecystectomy
Acute calculous cholecystitis
Persistent cystic duct obstruction leads to GB distension, wall inflammation & edema
Can lead to: empyema, gangrene, rupture Pain usu. persists >24hrs & a/w N/V/Fever
Palpable/tender or even visible RUQ mass Nuclear HIDA scan shows nonfilling of GB
If U/S non-diagnostic, obtain HIDA
Empyema of gallbladder
Pus-filled GB due to bacterial proliferation in obstructed GB. Usu. more toxic, high fever
Emphysematous cholecystitis
More commonly in men and diabetics. Severe RUQ pain, generalized sepsis. Imaging shows air in GB wall or lumen
Perforated gallbladder
Occurs in 10% of acute chol’y, usually becomes a contained abscess in RUQ
Acute acalculous cholecystitis
In 5-10% of cases of acute cholecystitis
Seen in critically ill pts or prolonged TPN
More likely to progress to gangrene, empyema, perforation due to ischemia
Caused by gallbladder stasis from lack of enteral stimulation by cholecystokinin
Cholangitis
Infection of the bile ducts due to CBD obstruction 2ndary to stones, strictures
Charcot’s triad seen in 70% of pts
May lead to life-threatening sepsis and septic shock (Raynaud’s pentad)
Reynolds pentad
A collection of signs and symptoms suggesting the diagnosis obstructive ascending cholangitis, a serious infection of the biliary system. It is a combination of Charcot’s triad (jaundice, fever, abdominal pain (usually RUQ)) with shock and altered mental status.
Indirect Hernia
(Congenital)
1. Through inguinal canal
- Passes through both deep and superficial inguinal rings.
- Distended mass is in spermatic cord (often found in scrotum/labia)
- Mass is lateral to inferior epigastric artery.
- 20x more in males
Direct Hernia
(Aquired)
- NOT through the inguinal canal
- Passes through weakness in abdominal wall
- Mass is adjacent to spermatic cord (rarely enters scrotum or labia)
- Medial to inferior epigastric artery
Cholendolithiasis
Gallstone in common bile duct
Primary = originates there
Secondary = from GB
