colon - anatomical relations and arterial supply Flashcards
what is anterior to the ascending colon?
Small intestine
Greater omentum
Anterior abdominal wall
what is posterior to the ascending colon?
Iliacus and quadratus lumborum
Right kidney
Iliohypogastric and ilioinguinal nerves
what is anterior to the transverse colon?
Greater omentum
Anterior abdominal wall
what is posterior to the transverse colon?
Duodenum
Head of the pancreas
Jejunum and ileum
what is anterior to the descending colon?
Small intestine
Greater omentum
Anterior abdominal wall
what is posterior to the descending colon?
Iliacus and quadratus lumborum
Left kidney
Iliohypogastric and ilioinguinal nerves
what is anterior to the sigmoid colon?
Urinary bladder
Uterus and upper vagina (females only)
what is posterior to the sigmoid colon?
Rectum
Sacrum
Ileum
what are attached to the surface of the large intestine?
omental appendices
what are omental appendices?
small pouches of peritoneum, filled with fat
what is running longitudinally along the surface of the large bowel?
three strips of muscle, known as the teniae coli
what are the three teniae coli?
the mesocolic, free and omental coli
what does the teniae coli contract to do?
to shorten the wall of the bowel
what does the teniae coli contracting and shortening the wall of the bowel produce?
producing sacculations known as haustra
how does the diameter of the large intestine compare to the small intestine?
The large intestine has a much wider diameter compared to the small intestine
where do the features in difference between large and small intestine cease?
at the rectosigmoid junction
what happens at the rectosigmoid junction?
the smooth muscle of the teniae coli broaden to form a complete layer within the rectum
what is the neurovascular supply to the colon closely linked to?
its embryological origin
what is the derivative of the midgut?
ascending colon and proximal 2/3 of the transverse colon
what is the derivative of the hindgut?
Distal 1/3 of the transverse colon, descending colon and sigmoid colon
what is the general rule of arterial supply to the midgut structures?
superior mesenteric artery
what is the general rule of arterial supply to the hindgut-derived structures?
inferior mesenteric artery
where does the ascending colon receive its arterial supply from?
from two branches of the superior mesenteric artery
what are the 2 branches of the superior mesenteric artery?
ileocolic and right colic arteries
what does the ileocolic artery give rise to?
gives rise to colic, anterior cecal and posterior cecal branches
what do the colic, anterior cecal and posterior cecal branches supply?
the ascending colon
what is the transverse colon derived from?
both the midgut and hindgut
what is the transverse colon supplied by?
branches of the superior mesenteric artery and inferior mesenteric artery
what are the branches of the superior and inferior mesenteric artery?
Right colic artery
Middle colic artery
Left colic artery
where is the right colic artery derived from?
superior mesenteric artery
where is the middle colic artery derived from?
superior mesenteric artery
where is the left colic artery derived from?
inferior mesenteric artery
what is the descending colon supplied by?
by a single branch of the inferior mesenteric artery; the left colic artery
where does the sigmoid colon receive its arterial supply via?
the sigmoid arteries
what are the sigmoid arteries branches of?
inferior mesenteric artery
what is the marginal artery (of Drummond)?
a clinically important vessel that provides collateral supply to the colon
what is the function of the marginal artery (of Drummond)?
maintaining arterial supply in the case of occlusion or stenosis of one of the major vessels
what happens as the terminal vessels of the superior mesenteric and inferior mesenteric artery approach the colon?
they split into many branches, which anastomose with each other.
what do the anastomoses form? what is it called?
These anastomoses form a continuous arterial channel which extends the length of the colon – the marginal artery
what arises from the marginal artery? what does it supply?
Long, straight arterial branches (called vasa recta) arise from the marginal artery to supply the colon.
