anterior abdominal wall Flashcards
what are the layers of the abdominal wall?
external intercostal
internal intercostal
innermost intercostal
what are the main muscles of the abdominal wall
external oblique
internal oblique
transversus abdominis
rectus abdominis
where does the external oblique run?
inferiorly and anteriorly until the aponeurosis
what is the aponeurosis
sheet of white fibrous tissue which takes the place of a tendon in sheet-like muscles
what is the most superficial abdominal muscle?
external oblique
where does the internal oblique run?
runs from ribs superiorly to iliac crest inferiorly
most middle layer
where does the rectus abdominis run?
from the xiphoid process to pubic synthesis
what causes the formation of a 6 pack in the rectus abdominis?
tendinous intersections
what is the linea alba?
fibrous section that runs down the midline the rectus abdominis
why does the aponeurosis attach to the linea alba?
no other points of bony attachment
what forms the rectus sheath?
formed by aponeurosis of the external oblique, internal oblique and transverse abdominis
what blood vessels innervate the abdominal wall?
internal thoracic arteries
what arteries does the internal thoracic arteries branch from?
subclavian
what do internal thoracic arteries turn into?
superior epigastric arteries
what do inferior epigastric arteries arise from?
external iliac artery
where is the inguinal ligament?
border between superior iliac spine and pubic tubercle
how is the inguinal ligament formed?
Aponeurosis of the external oblique (it’s inferior border) rolls under itself
what is found inside the inguinal canal?
femoral nerves, arteries and veins
also spermatic cord
where do the gonads develop before they descend?
abdominal wall
describe the route of descent of the testes?
develop in abdomen wall through pelvis through abdomen wall inguinal canals scrotum
what is a hernia
protrusion of the peritoneum and viscera (e.g. small intestine) through an opening or weakness
what is the most common type of abdominal hernia?
inguinal hernia
where do inguinal hernias occur?
at some point along the inguinal canal
why do inguinal hernias occur mainly in males?
they have a larger inguinal canal
what kind of hernias do women mainly get?
femoral hernias
what is the major risk of hernias?
blood supply being cut off - strangulation
what are the types of hernia and explain each?
direct - acquired, rarely enters scrotum
indirect - congenital, present from birth, commonly enters scrotum
why do direct hernias mainly occur in middle aged men?
may have gained weight more fat increases abdominal pressure
how is the gut split?
foregut
midgut
hindgut
what structures make up the foregut?
oesophagus, stomach, 1st part of the duodenum, liver pancreas and spleen
what vessel supplies the foregut?
coeliac trunk
when does the foregut become the midgut?
second part of duodenum
what structures are found in the midgut?
caudal duodenum, small and large intestine up to splenic flexure
what vessel supplies the midgut?
superior mesenteric artery
when does the midgut become the hindgut?
two thirds along the way of the transverse colon
what structures make up the hindgut?
splenic flexure, descending, sigmoid colon, rectum, upper anal canal
what vessel supplies the hindgut?
inferior mesenteric artery
what type of muscle makes up the oesophagus?
Upper 1/3 voluntary striated muscle
Lower 1/3 smooth muscle
what are the constrictions of the oesophagus and where are they found?
cervical - UOS
thoracic - when aortic arch and left main bronchus cross over the oesophagus
diaphragmatic - when the oesophagus passes into the diaphragm
where does the oesophagus enter the stomach?
cardinal orifice
what innervates the stomach?
vagus nerve
describe the structure and location of the upper oesophageal sphincter?
ring of skeletal circular muscle in the cricopharyngeus
found at the inferior border of the pharynx/superior border of the oesophagus
why is the lower oesophageal sphincter a physiological sphincter?
no thickening of muscle
what anatomical adaptations aid the lower oesophageal sphincter?
oesophagus enters the stomach at an acute angle
right crus of the diaphragm has a pinch-cock effect
what is the right crus of the diaphragm?
one of the muscular attachments of the diaphragm to the lumbar vertebrae
what are rugae?
folds of the stomach
what is the oesophagogastric junction?
change in mucosa from stratified squamous to simple columnar/glandular mucosa
what does the duodenum curve around?
the head of the pancreas
what are the parts of the duodenum
1 – superior, 2 – descending, 3 – horizontal, 4 – ascending
what feeds into the duodenum at the 2nd part?
bile duct and pancreatic duct
what are plicae circulares?
folds of the duodenum
where is the jejunum found?
left upper quadrant of the small intestine
where is the ileum found?
right lower quadrant of the small intestine
describe the differences between the jejunum and ileum
jejunum has
longer vasa recta
great vascularity
lots of plicae circularis
ileum has Peyer’s patches
what are haustra?
outward bubbles of the large intestine wall
what do haustra form?
semi lunar folds
what are tenia coli?
bands of longitudinal muscle which run the length of the large intestine
what are omental appendices?
fatty tags
what is the most common position of the appendix?
retro-caecal
