Colon Flashcards
what is the colon?
large intestine
where is the colon found?
a distal part of the gastrointestinal tract
where does the colon extend?
extending from the cecum to the anal canal
what does the colon receive and what is it’s function?
It receives digested food from the small intestine, from which it absorbs water and ions to form faeces
how can the colon be divided anatomically?
the colon can be divided into four parts – ascending, transverse, descending and sigmoid
what happens to the 4 sections of the colon?
These sections form an arch, which encircles the small intestine
how long is the average length of the colon?
150cm
which section does the colon begin with?
The colon begins as the ascending colon,
what is the ascending colon? where does it ascend from?
a retroperitoneal structure which ascends superiorly from the cecum.
what structure does the ascending colon meet?
right lobe of liver
what happens when the ascending colon meets the right lobe of the liver?
When it meets the right lobe of the liver, it turns 90 degrees to move horizontally
what is this 90 degrees turn known as?
This turn is known as the right colic flexure (or hepatic flexure)
what does the 90 degree turn of the ascending colon mark?
start of the transverse colon
what does the transverse colon cross?
the abdomen
where does the transverse colon extend from to?
extending from the right colic flexure to the spleen
what happens when the transverse colon extends to the spleen?
it turns another 90 degrees to point inferiorly
what is the transverse colon turn known as?
the left colic flexure (or splenic flexure)
what is the colon attached to when it points inferiorly?
the colon is attached to the diaphragm by the phrenicocolic ligament
what is the transverse colon like in terms of position? why?
variable in position
as transverse colon is the least fixed part of the colon
what can the transverse colon do in tall, thin individuals?
it can dip into the pelvis in tall, thin individuals
how is the transverse colon like?
Unlike the ascending and descending colons, the transverse colon in intraperitoneal
what happens for the colon to be termed the descending colon?
After the left colic flexure, the colon moves inferiorly, and so is termed the descending colon
what is the descending colon in terms of the peritoneal cavity?
It is retroperitoneal in the majority of individuals
where is the descending colon located?
anteriorly to the left kidney, passing over its lateral border
what happens when the descending colon begins to turn medially?
it becomes the sigmoid colon
how long is the sigmoid colon?
40cm long
where is the sigmoid colon located?
in the left lower quadrant of the adbomen
where does the sigmoid colon extend?
from left iliac fossa
where does the sigmoid colon extend to>
to the level of the S3 vertebra
what does the sigmoid colon’s journey give rise to?
characteristic “S” shape
what does the sigmoid colon attach to?
the posterior pelvic wall
what is the sigmoid colon attached to the posterior pelvic wall by?
by a mesentery
what is the attachment of the sigmoid colon to the posterior pelvic wall called?
the sigmoid mesocolon
what does the long length of the mesentery permit?
The long length of the mesentery permits sigmoid colon to be particularly mobile
what are the paracolic gutters?
two spaces between the ascending/descending colon and the posterolateral abdominal wall
why are the paracolic gutters important?
they allow infective material that has been released from abdominal organs to accumulate elsewhere in the abdomen
