GI and Liver Anatomy Flashcards
rectus abdominus
6 pack muscles
paired long muscles from sternum to pubis symphosis
surrounded by rectus sheath which is aponeuroses
‘tendinous intersections’ traverse them it and seperate them into distinct bellies
other abdominal muscles
- external oblique
- lateral to rectus abdominis
- runs downwards and inwards
- interdigitates with serratus anterior above it
- Internal oblique
- deep to the external obliques
- runs upwards and inwards
- Transverse abdominis
- deepest abdominal muscle
- Aponeurosis from these muscles wraps around the rectus abdominus and forms the rectus sheath
bony landmarks that define the boundaries of the abdomen
- Xiphisternum
- Costal margin
- Iliac crest
- Anterior superior iliac spine
- Pubic tubercle
- Pubic symphysis
9 abdominal regions and the boundaries of the lines
- verticle lines on both sides extend from the mid clavicular point to the mid-inguinal point
- the mid inguinal point is half way between the piubis symphysis and the anterior superior iliac spine
- the upper horizontal line is the subcostal plane
- this joins the costal margins on both sides
- the lower horizontal line is between the tubercles of the iliac crests
Mcburney’s point
- 2/3 of the way from the umbilicus to the right anterior superior iliac spine
- marks site of base of appendix
- gives a guide to the position of the caecum during clinical examination of the abdomen
transpyloric plane of addison
- lies roughly a hands breadth below the xiphisternum
- it crosses the epigastrum at the level that the midclavicular line crosses the costal margin
- structures that lie on this plane:
- gall bladder
- pancreas
- pylorus of the stomach
- duodenal-jejunal flexure
to which vertebra does the umbilicus correspond (only in a thin recumbent patient)
L3
intertubercular plane
- imaginary line between the two tubercles of the iliac crests
- it marks the position of the bifurcation of the abdominal aorta
- e.g. an aortic aneurism would only be felt above this poin t
what nerve supplies the foregut
- the greater splanchnic nerve (T5-T9)
- pain from the foregut is felt at the epigastrum
what nerve supplies the midgut
- the lesser splanchnic nerve
- T10-T11
- pain referred to the periumbilical area
what nerve supplies the hindgut
- Lowest splanchnic nerve
- T12
- pain is referred to the suprapubic area
pain of the peritoneum
- peritoneum has the same nerve supply as the skin
- disease that involves the gut wall is felt directly over where the cause of the pain is
what is the nerve supply to the diaphragm?
- the phrenic nerve
- C3, C4 and C5
- diseases that irritate the diaphragm are felt in the shoulder
sensory innervation of the kidney
- kidney and gonads are both supplied by the T10-T12 sympathetic plexus
- loin to groin referred pain for both areas
what is the T10 dermatome
the level of the umbilicus
what is the upper extent of the abdominal cavity?
- the under surface of the diaphragm reaches the 5th intercostal space
in what regions of the abdomen is the pain of the foregut, midgut and hindgut felt?
- foregut: epigastrium
- midgut: umbilical
- hindgut: suprapubic
describe the histology of the peritoneum
simple squamous epithelium
layers of peritoneum
- where it covers the abdominal wall: parietal peritoneum
- where it covers the viscera: visceral peritoneum
space between the two layers is the peritoneal cavity
linea alba
- fibrous structure that runs down the midline and seperates the rectus abdominus muscles
left triangular ligament
- to the left of the falciform ligament is the left lobe of the liver
- the peritoneum meets the falciform ligament and travels down it to become thee visceral peritoneum on the surface of the liver
- the left lobe of the liver attaches to the under surface of the diaphragm via a double layer of peritoneum called the left triangular ligament
the lesser omentum
- extends from the diaphragm down to the porta hepatis on one side and the duodenum on the other
- porta hepatis is where the portal vein and the hepatic artery enter the liver and where the bile duct leaves
- it is attached to the lesser curvature of the stomach
- the portal triad runs in the free edge of the lesser omentum
- behind this free edge where they run is the epiploic foramen (of winslow)
- the only way from the main peritoneal cavity into the lesser sac is through this foramen
spleen
well above the costal margin and can not usually be palpated
the greater omentum
- comes off greater curvature of the stomach
- has transverse colon attached to its deep surface
artery to the foregut, venous drainage and innervation
- the coeliac trunk
- branches from aorta just below diaphragm
- supplies
- lower third of the oesophagus until the 2nd part of the duodenum
- liver
- pancreas
- venous drainage is into the portal vein
- innervation is by the greater splanchnic nerve (T5-9)
- there’s parasympathetic innervation from the vagus
rugae
the folds on the inside of the stomach
which structures pass through the diaphragm with the oesophagus
the vagal trunks, the inferior oesophageal artery and vein
from where does the stomach recieve its nerve supply
Parasympathetic: vagus
sympathetic: greater splanchnic T5-T9
the coeliac trunk
after emerging from the aorta the coeliac trunk extends approximately 1cm before dividing into three major branches
- the splenic artery
- the common hepatic artery
- the left gastric artery
Splenic artery
- travels left to the spleen posteriorly to the stomach
- travels on the superior margin of the pancreas
- gives rise to the left gastro-epiploic
- this supplies the greater curvature of the stomach
- it anastomoses with the right gastroepiploic
- Pancreatic branches
- these supply the body and tail of the pancreas
- Short gastrics
- 5-7 small branches that supply the fundus of the stomach