GI: The abdominal wall Flashcards
What are the muscles of the abdo wall from superficial to deep?
Rectus abdominis - split in 2 by the linea alba and the edges form linea semilunaris. Has tendinous intersections that make the ‘6 pack’
External oblique - from ribs to aponeurosis
Internal oblique - from iliac crest to aponeurosis
Transversalis abdominis - from transverse process to aponeurosis
What is the arcuate/douglas’ line?
A horizontal line 1/3 of the distance from the umbilicus to the pubic symphysis.
Above the arcuate line the rectus abdominis is totally surrounded by aponeurosis
Below the arcuate line only the anterior of the rectus abdominis is covered by fascial sheathWh
What are some causes of periumbilical bruising?
- ruptured ectopic pregnancy
- blunt abdo trauma
- pancreatitis
- rectus sheath haematoma (increased risk if pt on warfarin, very painful due to swelling against tight sheath)
Where do you make the incision for an appendicectomy?
2/3rds of the distance between the umbilicus and anterior superior iliac spine
What is the consequence of a patent urachus?
Get urine leakage out of the umbilicus
Can present at birth or later in life - if men develop bladder outflow obstruction eg hypertrophic prostate the urine gets forced back up
What is Meckels diverticulum?
A bulge from the small intestine
A memory aid is the rule of 2s:
2% (of the population)
2 feet (proximal to the ileocecal valve)
2 inches (in length)
2 types of common ectopic tissue (gastric and pancreatic)
2 years is the most common age at clinical presentation
What is the difference between omphalocele and gastroschisis?
Omphalocele is an umbilical defect where there is a bulge of the bowel protruding out of the umbilicus. The bowel is covered in peritoneum and the condition is relatively easy to treat.
Gastroschisis is a defect in the abdo wall to the right of the umbilicus. The abdo contents such as the bowel and liver protrude out. They are not covered by peritoneum so susceptible to sepsis and necrosis. Much more serious
What is referred pain?
Pain is perceived at a site distant from the site causing the pain. Occurs because pain is caused to the proximal part of a somatic nerve but perceived by the brain to be in the distal dermatome.
What causes visceral pain? (generally)
Ischaemia, abnormally strong muscle contraction, inflammation stretch
The following DO NOT cause visceral pain - touch, burning, cutting, crushing
Where is foregut, midgut and hindgut pain?
Foregut pain - epigastric region
Midgut pain - periumbilical region
Hindgut pain - suprapubic
What structures are the foregut, midgut and hindgut?
Foregut: lower oesophagus to the 2nd part of the duodenum
Midgut: last part of the duodenum to 2/3 the way along the transverse colon
Hindgut: distal 1/3 transverse colon to rectum
Where is acute appendicitis pain located?
Early stage of appendicitis causes poorly localised pain in the periumbilical region
Then when it begins to irritate the peritoneum the pain localises to the right iliac region
Where are the common sites of referred cardiac pain?
Corners of mouth, left ear, neck, central chest, epigastric region, mainly left but sometimes right arm
What are the common sites of gall bladder pain?
Epigastric, actual location of gall bladder or on the back under right scapula
Describe these common abdominal incisions: Median Paramedian Transverse Suprapubic Subcostal McBurney
Median: an incision straight down the linea alba, curving around the umbilicus
Paramedian: Lateral to linea alba, provides access to kidney, spleen, adrenals
Transverse: lateral to umbilicus, used for colon, duodenum and pancreas
Suprapubic: 5cm above pubic symphysis, used for C sections
Subcostal: inferior to xiphoid process, used for gall bladder and spleen
McBurney: 2 perpendicular lines to split the fibres, used for appendectomies
