Flashcards in Session 3 - The mesenteries Deck (91):
What is the vitelline duct?
• A duct which leads to yolk sac
• Persistence leads to a number of different abnormalities
What is a patent vitellintestinal duct?
• Joins small intestine to umbillicus
What is a vitelline cyst?
• Vitelline duct forms fibrous strands at either end
What is a vitelline fistual?
• Direct communication between the umbilicus and the intestinal tract
Faecal matter comes out of umbilicus
What is the allantois?
• Placental exchange barrier
What occurs in a patent urachus?
Joins bladder to umbilicus
When can a patent urachus occur?
• Birth or later in life when men develop bladder outflow obstruction due to benign prostatic hypertrophy
What is Meckel's diverticulum?
• Most common GI abnormality
• Cul-de-sac in the ileum
What is the rule of 2's for Meckel's diverticulum?
• Effects 2% people, 2 feet from the iliocecal valve, 2 inches long, 2 types of tissue - Small bowel epithelium, gastric epithelium (Why?), 2:1 males to females
What is gastroichis?
• Failure of closure of the abdominal wall during folding of the embryo, leaving gut tub eand its derivatives outside the body cavity
• Viscera not covered by peritoneum
What is an omphalocoele?
• Persistence of physiological herniation
• Part of gut tube fails to return to abdominal cavity following normal herniation into abdominal cord
What is somatic referred pain?
• Pain caused by a noxious stimulus to the proximal part of a somatic nerve that is perceived in the distal dermatome of the nerve
• E.g. Shingles - pain felt distally along the nerve
What is visceral referred pain?
• In the thorax and abdomen, visceral afferent pain fibers follow sympathetic fibres back to the same spinal cord segments
• CNS perceives visceral (gut) pain as coming from superficial, somatic portions of the body supplied by relevant spinal cord segments
Give four factors which cause visceral referred pain
• Abnormally strong muscle contraction
Give four usually painful stimuli which do not cause referred pain
Define referred pain
• Pain perceived at a site distant from the site causing the pain
What is the vertebral level of the umbilicus?
What is the vertebral level of the pelvic brim?
Give two causes of referred pain?
• Right lower lobe pneumonia
Where can visceral foregut pain refer?
• Epigastric region
Where can midgut pain refer?
• Periumbilical region
Where can hindgut pain refer?
• Suprapubic region
What can damage to retroperitoneal structures cause?
• Central back pain
Where does early appendicitic pain localise?
Why does early appendicitic pain appear in the umbilicus?
• Innervation of appendix enters spine at T10
What does pain localise to lower quadrant in late stage appendicitis?
• Appendix becomes more inflamed and irritates surrounding bowel wall, localising the pain the right lower quadrant (irritates somatic nerve)
What is the anterior abdominal wall composed of?
• Skin, fasciae and muscle
Where does the anterior abdominal wall extend to and from?
• Anterior aspects of the rib cage and pelvic wall
What is knowledge of the composition of the abdominal wall used for?
• Surgical procedures
How many muscles are there in the antero-lateral abdominal wall?
• 3 flat
• 2 vertical
Where do the flat muscles on either side of the abdomen interlace?
• At the linea alba
What movements are the muscles of the abdomen useful for?
• Lateral flexion of the trunk
Other than movement, give one use of the abdominal muscles?
• Forced expiration during coughing
What does the location of a surgical incision depend on? (4)
• Type of surgical incision
• Location of abdominal viscera
• Avoidance of nerves
• Maintenance of blood supply
Where does small bower colic localise?
• Midgut, periumbilical
Give a cause of supapubic (hindgut pain)
• Large bowel colic
What is referred diaphragmatic irritation caused by?
• Ruptured spleen
• Ectopic pregnancy
• Perforated ulcer
What happens in referred diaphragmatic irritation?
• Blood pools in pelvis, causing pain
• Patient feels faint so lies down
• Blood rushes to diaphragm (C3/4/5)
• Presence of blood at diaphragm results in referred pain to left shoulder
Where is pain not referred to right shoulder in referred diaphragmatic irritation?
• Liver is in the way of blood on the way to the right diaphragm
What is contained within the peritoneal cavity?
• Periotneal fluid
How does the peritoneal cavity of men and women differ?
• In men peritoneal cavity completely closed
• In females there is a communication pathway to the exterior of the body through the uterine tubes, cavity and vagina.
Constitutes potential infective route
What does the parietal peritoneum line?
• The internal surface of the abdominal wall
What does the visceral peritoneum line?
• The intestines and gut contents
Does the parietal peritoneum touch muscle?
• Separated by extrapertioneal connective tissue
What is the extraperitoneal connective tissue attaching the parietal peritoneum to the anterior abdominal wall only lossely bound?
• To allow for changes in size of the bladder and rectum
How is the innervation, blood supply and lymphatics of the parietal peritoneum linked to the structures it lines?
• Same as the part of the abdominal wall it lines
What is the interior body of the wall sensitive to?
Where is pain not well localised in the peritoneal cavity?
• Inferior surface of the central part of the diaphragm
• Innervated by phrenic nerve which refers pain to shoulder
What is the blood supply, lymphatics and visceral nerve supply of the visceral peritoneum linked to?
• Same as organs it touches
What are the two main sensations the visceral peritoneum is sensitive to?
• Chemical irritation
What is a mesentery?
• A double layer or peritoneum that occurs as a result of the invagination of the peritoneum by an organ
• Connects an intraperitoneal organ to the body wall
What is an omentum?
• A double layered extension or fold of peritoneum that passes from the stomach and proximal parts of the duodenum to adjacent organs in the abdominal cavity
Made up of greater and lesser omentum
What is the greater omentum?
• A prominent, four layered peritoneal fold that hangs from the greater curve of the stomach
Adter descending it folds back and attaches to the anterior surface of the transverse colon
What is the lesser omentum?
• A small, double layered peritoneal fold that connects the lesser curvature of the stomach and the proximal part of the duodenum to the liver.
• Also connects stomach to portal triad
What is a peritoneal ligament?
• A double layer of pertoneum that connects an organ with another organ or the abdominal wall
What three things does the liver attach to?
• Anterior abdominal wall
How does the liver attacht he the anterior abdominal wall?
• Falciform ligament
What is the peritoneal cavity?
A potential space of capillary thinness between parietal and visceral layers of peritoneum
How does the liver attach to the duodenum?
• Hepatoduodenal ligament (the thickened free edge of the lesser omentum, which conducts the portal triad)
What four things does the stomach connect to?
• Inferior surface of the diaphragm
How does the liver attach to the stomach?
How does the stomach attach to the liver?
How does the stomach connect to the spleen?
• Gasrosplenic ligament
How does the stomach attach to the inferior surface of the diaphragm?
In what two ways can structures of the peritoneum be classified?
What is an intraperitoneal structure?
• Completely covered by peritoneum, however not completely enclosed in mesentery
How does the stomach attach to the transverse colon?
Gastrocolic ligament (greater omentum
What are the 9 retroperitoneal organs?
• SAD PUCKER
• Suprarenal glands
• Pancreas (head, neck and body)
Which organs are secondarily retroperitoneal (As a result of embryological development pushing)
• Ascending Colon
• Descending colon
What planes define the 9 surface regions of the abdominal wall?
• Midclavicular lines vertically
• Subcostal and transtubecular lines horizontally
What are the three side regions called?
• Left/Right hypo-chondriac region
• Left/right lumbar region
Left/Right Iliac region
What are the three middle parts of the abdominal wall called? (top to bottom)
• Epigastric region
• Umbilical region
• Hypogastric region
What divides the abdominal cavity into two compartments?
• The transverse mesocolon (mesentery of the transverse colon)
What are the two compartments of the abdominal cavity?
• Supracolic compartment
• Infracolic compartment
What is a retroperitoneal organ?
• Outside the peritoneal cavity and are thus only partially covered by parietal peritoneum
What is contained in the supracolic compartment?
What is contained in the infracolic compartment?
• Small intestine
• Ascending and descending colon
Where does the infracolic compartment lie?
• Posterior to the greater omentum
What is the infracolic compartment divided by?
• The mesenetery of the small intestine
• Into right and left infracolic spaces
How is communication between supracolic and infracolic spaces achieved?
• Paracolic gutters
What is the greater sac made up of?
• Supracolic and infracolic compartments
What is the lesser sac (omental bursa)?
• An extensive cavity that lies posterior to the stomach and the lesser omentum
What does the lesser sac allow?
Movement of the stomach
How do the greater and lesser sacs communicate?
• Through the omental foramen, an opening situated posterior to the free edge of the lesser omentum
What is the right subphrenic space?
• Lies between the diaphragm and the right lobe of the liver
• Common site for collections of fluid after right sided abdominal inflammation
What is the left subphrenic space?
• Lies between the diaphragm, left lobe of the liver, the stomach and the superior surface of the spleen
• Enlarged after splenectomy, when it is a common site for fluid collection
What is the recto-uterine pouch?
• Periotneum passes from the rectum to the posterior vagina, and then back to the uterine cervix and body.
What is the vesico-uterine pouch?
• Peritoneum spreads over the uterus to its anterior surface and as far as the cervic, before reflecting back on itself to meet the upper surface of the bladder
What is the recto-vesicle pouch?
• In males, peritoneum leaves junction of middle and lower thirds of the rectum, passng forwards to upper poles of the seminal vesicles and superior aspect of the bladder.
Between rectum and bladder it forums the rectovesical pouch
What is the mesentery of the small intestine?
• A broad, fan shaped fold connecting the coils of the jejunum and ileum to the posterior abdominal wall