Abdomen Flashcards
What are the 2 main divisions of the peritoneal cavity
Greater sac
Lesser sac
What divides the greater sac of the abdomen into 2
The mesentery of the transverse colon
What are the 2 compartments of the greater sac of the abdomen and what do they contain
Supracolic (above transverse mesocolon) - contains stomach, liver and spleen
Infracolic (below transverse mesocolon) - contains small intestine, ascending and descending colon
What divides the infra colic compartment of the greater sac
Root of the mesentery of the small intestine - divides it into left and right infra colic compartments
What connects the supracolic and infracolic compartments of the greater sac
Paracolic gutters
Lie between the posterolateral abdominal wall and the lateral aspect of the ascending/ descending colon
Where is the subphrenic recess found
Between the diaphragm and the liver
Left and right subphrenic recesses which are separated by the falciform ligament
On which side is a subphrenic abscess more common
Right sided
Due to increased frequency of appendicitis and ruptured duodenal ulcers
Where is the lesser sac found
Posterior to the stomach and the lesser omentum
What is the other name for the lesser sac
Omental bursa
What connects the omental bursa to the greater sac
The epiploic foramen
Where is the epiploic foramen found
Posterior to the free edge of the lesser omentum
In which sex is the peritoneal cavity not completely closed and why
Females
The uterine tubes open into the peritoneal cavity, providing a potential pathway between the female genital tract and the abdominal cavity.
Where is the rectovesical pouch found and what is it
In males
Between the rectum and bladder
It is a double fold of peritoneum
What is the equivalent of the rectovesical pouch in females
Rectouterine pouch (of Douglas) - double folding of peritoneum between the rectum and the posterior wall of the uterus
Vesicouterine pouch - Double folding of peritoneum between the anterior surface of the uterus and bladder
Where is Calot’s triangle found
At the aorta hepatis of the liver
What are the borders of Calot’s triangle
Medial - common hepatic duct
Inferior - cystic duct
Superior - inferior surface of the liver
What is the contents of Calot’s triangle
Right hepatic artery
Cystic artery
Lymph node of Lund
Lymphatics
What forms the right hepatic artery
Bifurcation of the proper hepatic artery into the right and left branches
What is parietal mesoderm derived from
Somatic mesoderm
What is visceral mesoderm derived from
Splanchnic mesoderm
Which abdominal organs are retroperitoneal
Suprarenal glands
Aorta/IVC
Duodenum
Pancreas
Ureters
Ascending and descending colon
Kidneys
Oesophagus
Rectum
Which part of the pancreas is intraperitoneal
Tail of pancreas
What are the attachments of the greater omentum
Descends from the greater curvature of the stomach and proximal part of the duodenum
Folds back up and attaches to the anterior surface of the transverse colon
How many layers of visceral peritoneum make up the greater omentum
4
Where does the lesser omentum attach
Lesser curvature of the stomach and proximal duodenum
to the Liver
What are the 2 parts of the lesser omentum
Hepatogastric ligament
Hepatoduodenal ligament
What is contained in the free edge of the hepatoduodenal ligament
Portal triad
What is the inguinal canal
A short passage extending inferiorly and medially through the inferior part of the abdominal wall, above the inguinal ligament
Is the inguinal canal above or below the inguinal ligament
Above
What is the opening of the inguinal canal known as
The deep inguinal ring
What is the exit of the inguinal canal known as
The superficial inguinal ring
What are the boundaries of the inguinal canal
Anterior - Aponeurosis of the external oblique, reinforced by the internal oblique laterally
Posterior wall - transversalis fasciae
Roof - Transversalis fascia, internal oblique, transversus abdominis
Floor - inguinal ligament, thickened medially by the lacunar ligament
What forms the deep inguinal ring
Transversalis fascia
What forms the superficial inguinal ring
Invagination of the external oblique
What is contained within the inguinal canal
Spermatic cord (males)
Round ligament (females)
Ilioinguinal nerve
Genital branch of the genitofemoral nerve
What is the mid inguinal point and what can be palpated here
Halfway between the pubic symphysis and the anterior iliac spine
Femoral pulse can be palpated
What is the mid point of the inguinal ligament and what is found here
Halfway between the pubic tubercle and the anterior iliac spine
Opening to inguinal canal just above this point
What is Hesselbachs Triangle
Also known as the inguinal triangle, is a region in the medial abdominal wall
What are the borders of Hesselbachs triangle
Medial - Lateral border of rectum abdomens
Lateral - inferior epigastric muscles
Inferior - inguinal ligament
What is the clinical importance of Hesselbachs triangle
An area of potential weakness
Site of direct inguinal hernia
Describe the arrangement of the superficial fascia of the anterior abdominal wall
Above the umbilicus - a single sheet of CT
Below the umbilicus - divided into two layers
What are the two layers of superficial fascia of the anterior abdominal wall below the umbilicus
Fatty superficial layer - Camper’s fascia
Membranous deep layer - Scarpa’s fascia
What are the 3 flat muscles of the abdominal wall
External oblique
Internal oblique
Trasnversus abdominis
The aponeurosis of the 3 flat muscles of the abdominal wall combine to form what
Linea Alba
Where does the Linea Alba extend to
From the Xiphoid process of the sternum to the pubic symphysis
Which is the largest flat muscle of the abdominal wall
External oblique
Where does external oblique attach
Ribs 5 -12
Iliac crest and pubic tubercle
What lies directly deep to external oblique
Internal oblique
Where does internal oblique attach
Inguinal ligament, iliac crest and lumbodorsal fascia Inserts onto ribs 10-12.
Where does transversus abdominis attach
Inguinal ligament, costal cartilages 7-12, iliac crest and thoracolumbar fascia
Inserts onto the conjoint tendon, xiphoid process, linea alba and pubic crest
What innervates the flat muscles of the anterior abdominal wall
Thoracoabdominal nerve (T7-T11)
Subcostal nerve
What additional nervous innervation does internal oblique and transversus abdominis have
Branches of the lumbar plexus
What are the two vertical muscles of the anterior abdominal wall
Rectus abdominis
Pyramidalis
Describe rectus abdominis
Long, paired muscle, found either side of the midline
Separated by the linea alba
Where does rectus abdominis attach
Crest of pubis bone
Inserts onto the xiphoid process of sternum, and costal cartilages of ribs 5-7
What innervates rectus abdominis
Thoracoabdominal nerve
Where is pyramidalis found and what is its action
Found superficially to the rectus abdominis
Tenses the linea Alba
Describe the rectus sheath
Formed by the aponeurosis of the three flat muscles (transversus abdominis, internal and external oblique) and encloses the rectus sheath and pyramidalis
What is the arcuate line and what occurs here
The line at which the posterior layer of the rectus sheath is deficient
The rectus abdominis is in direct contact with the transversalis fascia
What are the 5 muscles in the posterior abdominal wall
Iliacus
Psoas Major
Psoas minor
Quadratus lumborum
Diaphragm
What is the action of quadratus lumborum
Extension and lateral flexion of the vertebral column
Which muscle is found most superiorly in the posterior abdominal wall
Quadratus lumborum
What is the action of quadratus lumborum
Flexion at the thigh and hip
Lateral flexion of the vertebral column
Which posterior abdominal wall muscle is only present in 60% of the population
Psoas Minor
What is the action of iliacus
Flexion and lateral rotation of the thigh
What is a positive psoas sign
Pain elicited by flexion at the hip
What are the two layers of fascia in the posterior abdominal wall
Psoas fascia
Thoracolumbar fascia
At what level does the aorta bifurcate into its terminal branches
L4
WHat is the first branch of the abdominal aorta
Inferior phrenic arteries
At what level do the gonadal arteries branch from the aorta
L2
At what level does the aortic arch end
T4
What are the 3 main branches of the aortic arch (proximal to distal)
Brachiocephalic trunk
Left common carotid
Left subclavian
What are the branches of the descending aorta (in order)
Bronchial arteries - left form aorta, right from intercostals
Mediastinal arteries
Oesophageal arteries
Pericardial arteries
Superior phrenic arteries
Intercostal and subcostal
How many intercostal arteries branch from the aorta
9
What are the branches of the abdominal aorta
Inferior phrenic
Coeliac axis
Superior mesenteric artery
Middle suprarenal
Renal arteries
Gonadal arteries
Inferior mesenteric artery
Median sacral artery
Lumbar arteries
At what level does the coeliac axis branch from the aorta
T12
At what level does the SMA branch from the aorta
L1
At what level does the IMA branch from the aorta
L3
What is the last branch of the aorta and where does it branch
Median sacral artery
L4
How many pairs of lumbar arteries branch from the aorta
4
What are the 3 major branches of the coeliac axis
Left gastric
Splenic
Common hepatic
Describe the left gastric
Smallest of the 3 arteries
Ascends across the diaphragm, gives oesophageal branches, and continues along the lesser curvature of the stomach
Which artery does the left gastric anastomose with
Right gastric
In which structure is the splenic artery found
Splenorenal ligament
What are the 3 important branches of the splenic artery
Left gastroepiploic
Short gastrics
Pancreatic branches
What does the left gastroepiploic artery supply and what does it anastomose with
Greater curvature of the stomach
Anastamoses with the right gastroepiploic
What do the short gastric arteries supply
The fundus of the stomach
Which branch of the coeilac axis is the only one to go to the right
Common hepatic artery
What are the two branches of the common hepatic artery and where does it bifurcate
Proper hepatic
Gastroduodenal
Bifurcates at the superior aspect of the duodenum
What are the branches of the proper hepatic artery
Right gastric artery
Right and left hepatic
Cystic
What does the right gastric artery supply
Pylorus and lesser curvature of the stomach
What are the two branches of the gastroduodenal artey
Right gastroepiploic
Superior pancreaticoduodenal
Which is the only organ to receive blood supply from all 3 branches of the coeliac axis
Stomach
What are the two main branches of the pancreaticoduodenal arcade
Superior pancreaticoduodenal artery - a branch of the gastroduodenal artery
Inferior pancreaticoduodenal artery - branch of SMA
Which artery do posterior duodenal ulcers erode into
Gastroduodenal artery
What is coeliac trunk compression syndrome
Compression of the coeliac axis by the median arcuate ligament
What are the risk factors for a splenic arteyr aneurysm
Female sex
Multiple pregnancies
Portal HTN
Pancreatitis /Pseudocyst formation
What does the SMA supply
The Midgut
From the major papillae of the duodenum to the proximal 2/3 of the transverse colon
What is anterior to the SMA at its origin
Pyloric part of stomach
Splenic vein
Neck of pancreas
What is posterior to the SMA at its origin
Left renal vein
Ucinate process of the pancreas
Inferior part of the duodenum
What is the relationship between the SMA and the ucinate process of the pancreas
Ucinate process hooks itself around the back of SMA
What are the branches of the SMA
Inferior pancreaticoduodenal artery
Jejunal and ileal arteries
Middle colic artery
Right colic artery
Ileocolic artery
The appendicular artery is a branch of what atery
Ileocolic
What does the right colic artery supply
Ascending colon
What does the middle colic artery supply
Transverse colon
What are the vasa recta and how do they differ between the ileum and jejunum
Vasa recta - anastomotic arcades
Jejunal arteries - smaller number of arterial arcades, but they are longer
Ileal arteries - higher number of arterial arcades, they are shorter
Is the IMA intraperitoneal or an retroperitoneal structure ?
Retroperitoneal
What are the 3 major branches of the IMA
Left colic artery
Sigmoid artery
Superior rectal artery
What are the 2 branches of the left colic artery
Ascending
Descending
What does the descending left colic artery anastomose with
Superior sigmoid artery
In a left hemicolectomy what artery will they want a high resection of
IMA
What is the marginal artery of drummond
A continuous arterial circle long the inner border of the colon
What forms the marginal artery of drummond
branches from the ileocolic, right colic and middle colic of the SMA and left colic and sigmoid branches of the IMA.
What forms the Arch of Riolan
Anastamosis between the middle colic branch of SMA and left colic branch of IMA
What is meant by the splenic flexure being a watershed area
Has dual supply from two large arteries
What is the IVC formed by and at what level
Common iliac veins at L5
What are the tributaries of the IVC
Common iliac veins
Lumbar veins
Renal veins
Right testicular or ovarian veins
Right suprarenal veins
Inferior phrenic veins
Hepatic veins
Which structures do not have tributaries to the IVC and why
No tributaries from the spleen, pancreas, gallbladder or abdominal portion of GI tract
Drained by the portal system
What forms the portal vein and where
Union of the splenic vein and the SMV, posterior to the neck of the pancreas at level of L2
What are the tributaries to the portal vein
Right and left gastric veins
Cystic veins
Para-umbical veins
Which veins are tributaries to the splenic vein
Short gastric veins
Left gastro-omental veins
Pancreatic veins
IMV
Where does the IMV drain blood from
Rectum
Sigmoid colon
Descending colon
Splenic flexure
Where does the IMV pass in relation to the pancreas
Posterior to the body of the pancreas
Where does the SMV drain blood from
Small intestine, caecum, ascending colon and transverse colon
Where does the SMV pass in relation to the pancreas
Posterior to the neck of pancreas
What are the tributaries of the SMV
Right gastro-omental vein
Anterior and posterior inferior pancreaticoduodenal veins
Jejunal vein
Ileal vein
Ileocolic vein
Middle colic vein
Where is the origin of the SMV
RIF
Forms as a convergence of the veins draining the terminal ileum, caecum and appendix
Where are the sites of porto-systemic anastomosis
Oesophageal
Rectal
Retroperitoneal
Paraumbilical
Which veins from the oesophageal portosystemic anastomosis
Left gastric vein
Oesophageal tributaries of the azygous system
Which veins form the rectal portosystemic anastamosis
Superior and inferior rectal veins
Which veins form the retroperitoneal portosystemic anastamosis
Portal tributaries of the mesenteric veins and retroperitoneal veins
Which veins form the paraumbilical portosystemic anastamosis
Portal veins of the the liver and veins of the anterior abdominal wal
Which surface of the liver is its diaphragmatic surface
The anterosuperior aspect
Which surface of the liver is its visceral surface
Posteroinferior aspect
What organs are in direct contact with the liver
Right kidney
Right adrenal gland
Right colic flexure
Transverse colon
First part of the duodenum
Gallbladder
Oesophagus
Stomach
What does the falciform ligament attach to and what does it contain
Anterior abdominal wall
Contains ligamentum teres
What is the ligamentum teres a remnant of
Umbilical vein
What does the coronary ligament attach to and what does it demarcate
Attaches the superior surface of the liver to the inferior aspect of the diaphragm
Demarcates the bare area of the Liver
What are the coronary ligaments also known as
Anterior and posterior fold
What do the anterior and posterior folds (coronary ligaments) unite to form
The triangular ligaments of the liver
Right and left triangular ligament
What ligament surrounds the portal triad
Hepatoduodenal ligament
What are the ligaments of the liver
Falciform ligament
Coronary ligament (right and left folds)
Triangular ligaments (right and left)
Lesser omentum
Where is the subhepatic space found
Subdivision of the supra colic compartment, located between the liver and the transverse colon
What is Morrisons pouch
Potential space between the visceral surface of the liver and the right kidney
What is the fibrous layer of the liver known as
Glissons capsule
What are the two ‘accessory lobes’ of the liver and where do they arise from
Caudate lobe
Quadrate lobe
Arise from the right lobe of the liver
Where is the caudate lobe found
It lies between the IVC and a fossa produced by the ligamentum venous
Where is the quadrate lobe found
Between the gallbladder and a fossa produced by the ligamentum teres
What does the porta hepatis separate
The caudate and quadrate lobes
What are the 2 vessels supplying the liver and what do they proportionally supply
Hepatic artery proper - 25% of blood supply
Hepatic portal vein - 75% of blood supply
What is the nervous innervation of the Liver
Parenchyma of the liver innervated by the hepatic plexus
Glissons capsule - innervated by lower intercostal nerves
How is the lymphatic drainage of the liver split
Anterior
Posterior
What is the lymphatic drainage of the anterior liver
Hepatic lymph node s
What is the lymphatic drainage of the posterior liver
Phrenic
Posterior mediastinal nodes
What are the anterior and superior relations of the gallbladder
Inferior border of the liver
Anterior abdominal wall
What are the posterior and inferior relations of the gallbladder
Posterior - Transverse colon and proximal duodenum
Inferior - Biliary tree and remaining parts of duofenum
What are the 3 parts of the gallbladder
Fundus
Body
Neck
which is the largest part of the gallbladder
Body
The neck of the gallbladder tapers to become continuous with which structure
Cystic duct
Where is Hartmann’s pouch and what can get stuck there
A mucosal fold in the neck of the gallbladder
Gallstones can become lodged here
The cystic duct combines with what to form the common bile duct
Common hepatic duct
The common hepatic duct combines with which structure, where, to form the hepatopancreatico ampulla
Combines with the pancreatic duct
Enters the duodenum on the medial aspect of the 2nd part of the duodenum
What is the blood supply of the gallbladder
Cystic atery
What is the cystic artery a branch of
Hepatic artery
What is the venous drainage of the gallbladder
Cystic veins
Drain directly into the portal vein
Which organs is the pancreas in direct contact with
Stomach
Duodenum
Transverse mesocolon
Common bile duct
Spleen
What is the relation of the pancreas and the duodenum
The first part of the duodenum lies anteriorly
whereas the second part of the duodenum including the ampulla of Vater lies laterally to the right of the pancreatic head
The linorenal ligament connects which 2 organs
The spleen and the left kidney
Which vessels are related to the pancreas
Aorta and IVC
SMA
Hepatic portal vein - and the SMV and splenic vein prior to combining
What are the 5 parts of the pancreas
Head
Ucinate process
Neck
Body
Tail
Which part of the pancreas is intraperitoneal
Tail
What is the blood supply of the pancreas
Pancreatic branches of the splenic artery
Additional supply to the head - superior and inferior pancreaticoduodenal arteries which are branches of the gastroduodenal (from coeliac trunk) and superior mesenteric arteries, respectively
What is the venous drainage of the pancreas
Head - Superior mesenteric branches of the portal vein
Rest - pancreatic and splenic veins
What is the lymphatic drainage of the pancreas
Pancreaticosplenal nodes
What are the 2 ligaments which connect the spleen to the stomach and kidneys
Gastrosplenic ligament
Splenorenal ligament
Which borders of the spleen contain notches
Anterior and superior borders
What is found anterior to the spleen
Stomach
What is found posterior to the spleen
Diaphragm
Left lung
Ribs 9-11
What is found inferior to the spleen
Left colic flexure
What is found medial to the spleen
Left kidney
Tail of pancreas
What is the arterial supply of the spleen
Splenic artery
Branches into 5 separate branches
What is the venous drainage of the spleen and what does this eventually form
Splenic vein
Combines with SMV to form portal vein
What are the relations of the right adrenal gland
Anterior - IVC, Right lobe of liver
Posterior -Right crus of diaphragm
What are the relations of the left adrenal gland
Anterior - stomach, pancreas, spleen
Posterior - Left crus of diaphragm
What is the embryological origin of the adrenal gland
Cortex -mesoderm
Medulla - ectodermal neural crest cells
What are the 3 zones of the adrenal cortex and what do they secrete
Zona glomerulosa - mineralocorticoids
Zona fasciularis - corticosteroids
Zona reticularis - androgens
What is the blood supply of the adrenal glands
Superior, middle and inferior adrenal arteries
What is the origin of the superior adrenal artery
Inferior phrenic artery
What is the origin of the middle adrenal artery
Abdominal aorta
What is the origin of the inferior adrenal artery
Renal arteries
What does the right adrenal vein drain into
IVC
What does the left adrenal vein drain into
Left renal vein
What layers enclose the kidney
Deep to superficial
Renal capsule
Perirenal fat
Renal fascia
Pararenal fat
What is the renal fascia also known as
Gerotas fascia
Which muscles lie posterior to the kidneys
Psoas major
Quadratus lumborum
Transversus abdominis
What is the line of brodel in the kidney
The avascular plane of the kidney, delineating the section of the kidney supplied by the anterior and posterior divisions
Found along the lateral and posterior border of the kidney
The renal artery branches are anatomical end arteries - why is this important
There is no communication between vessels - therefore damage to a vessel will lead to necrosis of the renal parenchyma
The arterial supply to the kidneys divide it into what 5 segments
Apical
Upper
Middle
Lower
Posterior
What structure does the left renal vein lie over
The abdominal aorta
Where does lymph from the kidneys drain
Para-aortic lymph nodes
What is the function of the abdominal mesentery
Suspends the small and large intestines from the posterior abdominal wall
Provides conduit for blood vessels
Which part of the mesentery is flattened against the posterior abdominal wall
Right mesocolon
Left mesocolon
Medial mesosigmoid
The parts of the mesentery that are flattened against the posterior abdominal wall are attached to this by what
Toldt’s fascia
Which major blood vessels are found in the mesentery
SMA and SMV
IMA and IMV
Where does the inferior mesenteric lymph nodes receive lymph from
Hindgut organs
Where do the inferior mesenteric lymph nodes drain into
Superior mesenteric lymph nodes
Where does the superior mesenteric lymph nodes receive lymph from
Midgut
Inferior mesenteric lymph nodes
Where do the superior mesenteric lymph nodes drain into
Para aortic nodes
How long is the oeosphagus, where does it start and end
25 cm
Starts at C6
Ends at T11
Describe the muscualr layer of the oesophagus and how it differs in different thirds
External layer of longitudinal muscle - differs - superior third is voluntary striated, middle third - voluntary striated and smooth, lower third - smooth muscle
Internal layer of circular muscle
WHat is the mucosa of the oesphagus
non-keratinised stratified squamous epithelium (contiguous with columnar epithelium of the stomach).
Which of the two oesophageal sphincters are anatomical
Upper
How could you describe the lower oesophageal sphincter and what maintains it
Physiological sphincter
Maintained by:
1. Oesophagus enters stomach at an acute angle
2. Walls of the intra-abdominal section of the oesophagus are compressed when there is a positive intra-abdominal pressure.
3.Prominent mucosal folds at the gastro-oesophageal junction aid in occluding the lumen.
4. Right crus of the diaphragm has a “pinch-cock” effect.
Where are the 4 phsyiological constrictions of the oesophagus
Arch of aorta
Bronchus
Cricoid cartilage
Diaphragmatic hiatus
What nerve is closely related to the oesophagus in the abdomen
Right and left vagus nerves
What is the arterial supply of the thoracic oesophagus
Thoracic aorta
Inferior thyroid artery
What is the arterial supply of the abdominal oesophagus
Left gastric artery
What is the venous drainage of the thoracic oesophagus
Azygous veins
Inferior thyroid vein
What is the venous drainage of the abdominal aorta
Portal circulation - via left gastric vein
Systemic circulation - via azygos vein
Nerve fibres from which nucleus supply the upper oesophageal sphincter
Nucelus ambiguus
Nerve fibres from which nucleus supply the lower oesophageal sphincter
Dorsal motor nucleus
The superior third of the oesophagus drains to which nodes
Deep cervical nodes
The middle third of the oesophagus drains to which nodes
Superior and posterior mediastinal nodes
The inferior third of the oesophagus drains to which nodes
Left gastric and coeliac nodes
What are the 4 main divisions of the stomach
Cardia
Fundus
Body
Pylorus
The transpyloric plane is at what level
L1
Which arteries supply the greater curvature of the stomach
Short gastric arteries
Right and left gastro-omental arteries
Which arteries supply the lesser curvature of the stomach
Left gastric artery
Right gastric branch of the hepatic artery
Which structures are found anterior to the stomach
Diaphragm
Greater omentum
Anterior abdominal wall
Left lobe of liver
Gall bladder
Which structures are found posterior to the stomach
Lesser sac
Pancreas
Left kidney
Left adrenal gland
Spleen
Splenic artery
Transverse mesocolon
The hepatogastric ligament attaches to which surface of the stomach
Lesser curvature
The pyloric sphincter is what kind of sphincter
Anatomical sphincter
The right gastric artery is a branch of which artery
Proper hepatic artery (branch of common hepatic)
right gastro-omental artery is a branch of which artery
Terminal branch of gastroduodenal artery (common hepatic)
Left gastro-omental artery is a branch of which artery
Splenic artery
The right and left gastric veins drain into
Portal vein
The short gastric vein, left and right gastro-omental veins drain into
SMV
Lymph drainage of the stomach is to
Gastric and gastro-omental lymph nodes
Which drain to coeliac lymph nodes
What are the 3 parts of the small intestine
Duodenum
Ileum
Jejunum
How long is the duodenum and what are its 4 parts
approx 25 cm
Superior, descending, inferior, ascending
Which part of the duodenum is at the level of L1
Superior
Which part of the duodenum is connected to the liver by the hepatoduodenal ligament
Superior duodenum
Which part of the duodenum is intraperitoneal
Superior
Which part of the duodenum is related to the IVC and aorta
Inferior
Where is the suspensory muscle of the duodenum found and what is its function
Found at the duodenojejunal junction
Contraction of the muscle widens the duodenojejunalflexure, aiding in movement of intestinal contents into the jejunum
What is a complication of duodenal ulcers
Erosion of the gastroduodenal artery - subsequent haemorrhage
Which parts of the small intestine are intraperitoneal
Jejunum
Ileum
Summarise the jejunum
Located in left upper quadrant
Thick intestinal walls
Long, straight vasa recta with less arcades
Red in colour
Summarise the ileum
Located in right upper quadrant
Thin intestinal walls
Short vasa recta, with more arcades
Pink in colour
What are the 2 arterial supplies to the duodenum and what landmarks marks the change
Gastroduodenal artery (common of right hepatic - coeliac trunk)
Inferior pancreaticoduodenal artery (branch of SMA)
Changes at major duodenal papilla (in 2nd part of duodenum)
The appendicular artery arises from which main artery
Ileocolic artery
Branch of the SMA
Where is McBurneys point
Situated one third of the distance from the right anterior superior iliac spine to the umbilicus
Where does lymph from the appendix drain
Ileocolic lymph nodes
What is the function of the ileocolic valvce
prevents reflux of large bowel contents into the ileum during peristalsis and is thought to function passively
What is the lymphatic drainage of the caecum
Ileocolic lymph nodes
How long is the colon
150cm
what does the phrenicocolic ligament attach to
The transverse colon
The diaphragm
Where is the sigmoid colon found
Left lower quadrant
From the left iliac fossa to the level of the S3 vertebra
What are the tenia coli
3 strips of muscle running longitudinally along the colon
Mesocolic, free and omental coli
What is the arterial supply of the ascending colon
Ileocolic artery
Right colic artery
What is the arterial supply of the transverse colon
Right colic artery
Middle colic artery
Left colic artery - branch of IMA
What is the arterial supply of the descending colon
Left colic artery
Why is the marginal artery of Drummond important
Provides collateral blood supply to the colon
Where does the superior mesenteric and inferior mesenteric veins drain into
Portal vein
What is the nervous innervation of midgut structures
Sympathetic, parasympathetic and sensory supply via nerves from the superior mesenteric plexus
What is the nervous innervation of hindgut structures
From the inferior mesenteric plexus
Parasympathetic innervation via the pelvic splanchnic nerves
Sympathetic innervation via the lumbar splanchnic nerves
What is the lymphatic drainage of the colon
Ascending and transverse colon - superior mesenteric nodes
Descending and sigmoid colon - inferior mesenteric nodes
What are the 2 major flexures of the rectum
Sacral flexure – anteroposterior curve with concavity anteriorly
Anorectal flexure – anteroposterior curve with convexity anteriorly.
What forms the sacral flexure of the rectum
The curve of the sacrum and coccyx
What forms the anorectal flexure of the rectum
The tone of puborectalis muscle
What is the final segment of the rectum called and what is its function
Ampulla
relaxes to accumulate and temporarily store faeces until defecation occurs
Describe the peritoneal coverings of the rectum
Superior third - anterior and middle sides are covered with peritoneum
Middle third - anterior peritoneal covering
Lower third - no peritoneum associated with it
What is the arterial supply of the rectum
Superior, middle and inferior rectal artery
What is the origin of the superior rectal artery
IMA
What is the origin of the middle rectal artery
Internal iliac artery
What is the origin of the inferior rectal artery
Internal pudendal artery
Which rectal veins drains into portal circulation and which into systemic circulation
Superior rectal vein - portal circulation
Middle and inferior rectal vein - systemic circulation
What is the sympathetic innervation of the rectum
Lumbar splanchnic nerves
Superior and inferior hypogastric plexuses.
What is the parasympathetic innervation of the rectum
S2-4 via the pelvic splanchnic nerves and inferior hypogastric plexuses
What is the lymphatic drainage of the rectum
Pararectal nodes
Lower rectum - drains directly into internal iliac nodes
Describe the internal anal sphincter
Surrounds the upper 2/3 of the anal canal
It is formed from a thickening of the involuntary circular smooth muscle in the bowel wal
Describe the external anal sphincter
Voluntary muscle that surrounds the lower 2/3 of the anal canal (and so overlaps with the internal sphincter). It blends superiorly with the puborectalis muscle of the pelvic floor.
What form the anorectal ring
Fusion of the Internal and external anal sphincter and puborectalis muscle
What is the pectinate line
The line in which the anal valves are found
Delineates the different embryological origins of the anal canal
What is the anal canal lined with superior to the pectinate line
Columnar epithelium
What is the anal canal lined with inferior to the pectinate line
Non keratinised stratified squamous epithelium
What is the arterial supply of the anal canal
Above the pectinate line - superior rectal, + anastomosis with middle rectal
Below pectinate line - inferior rectal + anastomosis with middle rectal
What is the venous drainage of the anal canal
Above the pectinate line - superior rectal vein draining into portal system
Below pectinate line - inferior rectal into the pudendal into systemic
What is the lymphatic drainage of the anal canal
above pectinate line - Internal iliac nodes
Below pectinate line - superficial inguinal nodes
