The abdominal wall and the intestines Flashcards
What is the costal margin?
- The lower edge of the thorax
- Formed by the bottom edge of the rib cage (ribs 7-10)
Where does the umbilicus lie?
Dermatome 10
Where is the trans-pyloric plane of the abdomen and what does it cross?
- At the level of the 9th costal cartilage
- At L1
- Crosses the pyloric part of the stomach (where the stomach enters into the duodenum)
Where is the trans-tubercular plane of the abdomen and what does it cross?
At L5
Crosses the tubercule of the pelvis
What is the tubercule of the pelvis?
- Prominent forward projecting part of the pelvis
- Upper border of the medial portion
- Where the inguinal ligament attaches to
Where are the imaginary vertical lines drawn from, which split the abdomen into its parts?
The mid-clavicular lines
What are the 2 imaginary horizontal lines which split the abdomen into its 9 regions?
Trans-pyloric plane
Trans-tubercular plane
What are the 9 regions of the abdomen and where are they in relation to each other?
Umbilical – central region
Epigastric – Above the umbilical region and just below the sternum
Hypochondriac – Either side of the epigastric
Lumbar – Either side of the umbilical
Hypogastric – Below the umbilical
Iliac – either side of the hypogastric
Which region does the appendix lie?
In the RIGHT iliac region
What are the muscle layers of the abdominal wall?
External oblique
Internal oblique
Transverse abdominus
Where do the external oblique muscles originate and where do they connect to?
- Which direction do they travel?
- 5th to 12th rib
- Anterior iliac crest, linear alba, pubis
- Travel down and medially
What do the external oblique muscles help the trunk to do?
Rotate (to the opposite side)
Both help to flex forwards
Bend (to that side)
What does the external oblique become inferiorly?
The inguinal ligament
Where do the internal oblique muscles originate and where do they connect to?
- Which direction do they travel?
- Inguinal ligament, iliac crest
- Posteriorly to the lumbar fascia
- To inferior border of ribs 9-12
- Upwards and medially
What is the function of the transverse abdominis?
Thoracic and pelvic stability
Where do the transverse abdominis arise from?
- Ribs 7-12 (interdigtates with the diaphragm)
- Lumbar fascia posteriorly
Where is the insertion of the transverse abdominsis?
Linear alba and pubis
What is the function of the internal oblique muscles?
- Flex trunk forwards
Each muscle:
- Bend to the same side
- Rotate front of abdomen to the same side
What is the origin of the rectus abdominis?
5-7 costal cartilages and xiphoid
What is the insertion of the rectus abdominis?
1inch into the pubis crest
What is the function of the rectus abdominis?
- Flexes abdominal column
- Tenses anterior abdominal wall
What is the function of ALL of the abdominal muscles?
Compress abdominal contents
What happens to the aponeurosis of each muscle ABOVE the arcuate line?
- External oblique and anterior internal oblique makes the anterior rectus sheath
- Posterior internal oblique aponeurosis and the aponeurosis of the transverse abdominis forms the posterior sheath
What happens to the aponeurosis of each muscle BELOW the arcuate line?
- All aponeurosis pass infront of the rectus - forming the anterior sheath
- Posterior sheath made of transversalis fascia and the peritoneum below this
What is the arcuate line of Douglas?
Horizontal line - sets the boundary of the lower limit of posterior layer of recuts sheath
What is the aponeurosis of the muscle?
- Flattened sheet
- Made of connective tissue and collagen
- Envelope the muscle and connect them together
What does the peritoneum do?
Form the lining of the abdominal cavity
What is the greater omentum and where does it lie?
- Apron-like fold of visceral peritoneum, which hangs down in front of the stomach
- Lies over the transverse colon and small intestine
What is the small intestine split into?
Duodenum
Jejunum
Ileum
Does the colon have vili?
No - has crypts
Where does most the absorption take place?
In the jeujunum of the small intestine
What is the shape of the duodenum?
- C shaped around the head of the pancreas
- 4 distinct sections
Where does the duodenum lie?
Adjacent to the stomach
What is the blood supply to the duodenum?
- Superior pancreaticoduodenal artery (from the gastroduodenal artery)
- Inferior pancreaticoduodenal artery (from the superior mesenteric artery)
What are PLICAE CIRCULARIS?
Large valvular flaps projecting into the lumen of the small intestine - has villi
Where does the jejunum lie in the body?
In the umbilical region
What are the differences between the jejunum and the ileum?
Ileum has thinner walls and a smaller diameter
Ileum has more fat (mesentery) than the jejunum
Ileum has more peyers patches
Ileum is supplied by shorter and more numerous arcades of the mesenteric vessels
(ileum 3-5 arcades. jejunum 1-2 arcades)
What does the ileum absorb?
Vitami B12
Where does the ileum lie?
In the suprapubic and pelvic region
What can be identified where the ileum joins to the caecum?
- Ileocecal fold
- Appendix
- Mesoappendix
What is the ileocaecal fold?
Fold of peritoneum
What is the ileocaecal junction?
Where the ileum meets the caecum of the large intestine
What is the ileo-caecal valve?
Spinchter muscle valve which separates the ileum from the caecum
What are the parts of the large intestine?
- Caecum
- Ascending colon
- Hepatic flexure
- Transverse colon
- Splenic flexure
- Descending colon
- Sigmoid colon
- Rectum
- Anal canal
Where is the rectum located in the body?
Anterior to the 3rd segment of the sigmoid colon
Where does fluid get absorbed in the body?
In the colon
What are the aterial branches from the aorta?
- Celiac trunk
- Supra renal
- Renal
- Superior mesenteric
- Inferior mesenteric
What are the arterial branches from the celiac trunk and which direction do they travel?
- Left gastric (to the left)
- Splenic (to the left)
- Common hepatic (to the right)
What are the branches from the splenic artery?
- Short gastric
- Left gastroepiploic
What are the branches from the common hepatic?
- Propper hepatic
- Gastrodueodenal
What are the branches from the propper hepatic?
- Left and right hepatic
- Right gastric
Where does the cystic artery branch from?
The right hepatic artery
What are the branches of the gastroduodenal artery?
- Right gastroepiploic
- Supraduodenal
- Superior pancreaticoduodenal
- Pre pancreatic
What are the branches from the superior mesenteric aretery?
- Inferior pancreaticoduodenal
- Middle colic
- Right colic
- Jejunal arteries
- Ileocolic
What are the branches from the inferior mesenteric artery
- Left colic
- Superiror and inferior rectal arteries
- Sigmoid
What are the branches from the ileocolic?
- Ileal arteris
- Appendicular arteries
What do the colic arteries supply?
The colon
What does the terminus of the abdominal aorta split into?
The right and left common iliac arteries
What do the right and left common iliac arteries split into?
Internal and external iliac arteries
What are the 3 main features of the large intestine?
1) Appendices epiploicae
2) Haustrations
3) Taenia coli
What are appendicies epiploicae?
Fatty tags
What are taenia coli and how do that cause haustrations to form?
- 3 bands of longitudinal smooth muscle
- Shorter than the rest of the layers of the large intestine
- When contract the cause the small bunches - haustrations
Which parts of the colon are completely peritonealised and which are attached directly to the posterior abdominal wall?
- Transverse colon and sigmoid - peritonealised
- Ascending and descending - attached to wall
Where does the the appendix arise from?
The posteriomedial aspect of the caecum
Where does the ceoliac axis arise from the aorta?
T12
Where does the superior mesenteric artery arise from the aorta?
L1
Where does the inferior mesenteric artery arise from the aorta?
L3
What does the ileocolic artery supply?
- The terminal ileum
- Caecum
- Start of ascending colon
What does the right colic artery supply?
The ascending colon
What does the middle colic artery supply?
The transverse colon
What does the left colic artery supply?
The descending colon
Which structures are intraperitoneal?
Stomach
Jejunum
Ileum
Transverse colon
Liver
Gallbladder
Which structures are RETROPERITONEAL?
- Pancreas
- Duodenum
- Ascending colon
- Descending colon
- Oesophagus
- Rectum
Where does the blood supply for the oesophagus come from?
The coeliac trunk
What is Merckel’s diverticulum and where is it found?
Remains of the embryonic vitello-intestinal duct
- On the anti-mesenteric border of the bowel (small intestine)
- 2ft away from the ileocaecal junction