Abdominal Pain and the Likely Source Flashcards
what are the components of the large intestine?
colon: caecum, appendix, ascending colon, transvrse colon, descending colon, sigmoid colon
rectum
anal canal
anus
what is included in the foregut?
oesophagus to mid-duodenum
liver + gall bladder
spleen
1/2 of pancreas
what is included in the midgut?
mid-duodenum to proximal 2/3rds of transverse colon
1/2 of pancreas
what is included in the hindgut?
distal 1/3rd of transverse colon to proximal 1/2 of anal canal
what are the 4 quadrants of the abdomen?
right/left upper
right/left lower
(separated at level of umbilicus)
what are the 9 regions of the abdomen?
what divides them?
right/left hypochondrium right/left lumbar right/left inguinal epigastric, umbilical, pubic down the middle 2 mid-clavicular planes subcostal plane transtubecular plane
what are the muscles of the anterolateral abdominal wall?
rectus abdominus (6 pack) external obliques, internal obliques, transversus abdominis rectus abdominis
what is the function of the anterolateral abdominal wall muscles?
contract to guard organs in threat of injury or peritonitis
describe the peritoneum
thin, transparent, semi-permeable, serous membrane
abdominal organs develop into the peritoneum like a fist into a balloon, true of false?
true
what are the functions of the peritoneum?
lines walls of abdominopelvic cavity (parietal) and organs (visceral)
forms peritoneal cavity containing lubricating fluid to help gut move
how can peritonitis occur?
blood, pus or faeces (due to trauma) can enter peritoneal cavity and travel around causing inflammation of peritoneum
what are intraperitoneal organs?
completely surrounded inperitoneum, barely mobile
stomach, liver/gall bladder, spleen, parts of small and large intestine
what are organs with a mesentery?
covered in visceral peritoneum which wraps behind the organ to form a double layer which attaches it to body wall (mesentery) making it mobile
small intestine
what are retroperitoneal organs?
only anterior surface covered in peritoneum as resting on body wall kidneys adrenal gland pancreas ascending/descending colon
name 3 formations of peritoneum which form due to rotation of GI tract during development
mesentery
omentum
peritoneal ligaments
what are the components and function of mesentery?
attach organs tomposterior body wall providing high mobility
contain blood/lymph vessels, nerves, lymph nodes and fat
what are the 3 mesenterys?
mesentery proper: small intestine
transverse and sigmoid mesocolon
mesoappendix
describe the structure and function of the greater omentum
4 layered apron like structure that hangs over organs
attaches greater curvature of stomach to transverse colon
describe the structure and function of the lesser omentum
double layered
2 parts: attaches liver to stomach and liver to duodenum
has a free edge which contains portal triad
dives peritoneal cavity into greater/lesser sac
how do the greater and lesser sac communicate?
via the omental foramen (foramen of winslow)
what lies in the free edge of the lesser omentum?
the portal triad (bile duct, hepatic artery, portal vein)
what are the 2 ligaments of the lesser omentum?
hepatogastric ligament hepatoduodenal ligament (free edge)
what are the 2 ligaments of the greater omentum?
gastrosplenic ligament
slenorenal ligament
what are the male/female pouches of peritoneum that drape over the pelvic organs?
male = rectovesical pouch female = vesico-uterine pouch, recto-uterine pouch (pouch of douglas)
what is ascites and what causes it?
collection of fluid in the peritoneal cavity
caused by cirrhosis/portal hypertension
how is ascites drained and where is this done?
abdominocentesis
needle placed lateral to rectus sheath to avoid inferior epigastric artery
what is visceral/somatic pain like?
visceral = dull, aching somatic = sharp, stabbing
what nerves supply the organs of the abdominal cavity?
visceral afferents (sensory) enteric nervous system autonomic motor nerves (parasympathetic/sympathetic)
what nerves supply the abdominal wall?
somatic sensory
somatic motor
sympathetic nerve fibres
how do sympathetic nerves get from CNS to abdominal organs?
leave spinal cord at T5-L2
enter sympathetic chains
leave chains within abdominopelvic splanchic nerves
synapse at prevertebral ganglia anterior to branches of abdominal aorta
Post synaptic sympathetic nerves pass from prevertebral ganglia onto surface of abdominal aorta branches
These nerves take part in periarterial plexuses as they hitch a ride with the arteries and their branches to the organs
how do sympathetic nerves get from the CNS to the adrenal gland?
leave spinal cord (T10-L1) enter abdominopelvic splanchnic nerves don't synapse at prevertebral ganglia carried with periarterial plexuses to the adrenal gland synapse directly onto cells
how does the parasympathetic vagus nerve get from the CNS to the abdominal organs?
presynaptic parasympathetic nerve fibres enter abdominal cavity on the surface of the oesophagus (vagal trunks)
travel into the periarterial plexuses around abdominal aorta
carried to walls of organs where they synapse in ganglia
which regions does pain in the foregut, midgut and hindgut refer to?
foregut = epigastric midgut = umbilical hindgut = pubic
how do visceral afferents get from abdominal organs to CNS?
run alongside sympathetic fibres back to the spinal cord Foregut = T6-T9 Midgut = T8-T12 Hindgut = T10-L2 Pain is therefore felt in the dermatomes
what 4 nerves are the somatic motor, somatic sensory and sympathetic nerves supplying the body wall conveyed within?
thoracoabdominal nerves (7th-11th intercostal nerves) subcostal nerve (T12 anterior ramus) Iiohypogastric nerve (half of L1 anterior ramus) Ilioinguinal nerve (other half of L1 anterior ramus)
why does appendicitis start as dull and achy in the umbilical then becomes sharp and stabbing in the right iliac region?
pain from midgut radiates to umbilical region (due to visceral afferents entering spinal cord there)
as appendix gets more inflamed it irritates the parietal peritoneum in the right iliac fossa causing sharp pain there
