anatomy of large intestine, its section, ceacum, ascending colon, transverse colon, descending colon, sigmoid colon, functions of large intestine , relations of each components of large intestine, carddinal siggns of large intestine, iliocecal junstion, difference between large and small intestine. abdominal angina, superior mesenteric and inferior mesenteric artery, lymphatic drainage, colonoscophy,

1. Dr SANA YASEEN
ANATOMY DEPT.
LARGE
INTESTINE

3.  large intestine, also known as the large bowel or colon,
is the last part of the gastrointestinal tract and of the
digestive system
 1.5 metres (5 ft) long,
 1/5 of the whole length of the gastrointestinal tract
Sections of the colon are:
 The ascending colon including the cecum and appendix
 The transverse colon including the colic flexures and
transverse mesocolon
 The descending colon
 The sigmoid colon – the s-shaped region of the large
intestine
 Rectum
 Anal canal

4. Functions of large intestine
 3 primary functions:
1. absorbing water and electrolytes,
2. producing and absorbing vitamins,
3. forming and propelling feces toward the
rectum for elimination. Convert the liquid
contents of the ileum into semisolid feces by
absorbing water, salts, and electrolytes. It
also stores and lubricates feces with mucus.

5.  By the time indigestible materials have reached the
colon, most nutrients and up to 90% of the water
has been absorbed by the small intestine.
 The role of the ascending colon is to absorb the
remaining water and other key nutrients from the
indigestible material, solidifying it to form stool.
 The descending colon stores feces that will
eventually be emptied into the rectum.
 The sigmoid colon contracts to increase the
pressure inside the colon, causing the stool to move
into the rectum.
 The rectum holds the feces awaiting elimination by
defecation.

8.  Is characterized by the following:
1. Teniae coli: three narrow bands of the outer
longitudinal muscular coat.
2. Sacculations or haustra: produced by the teniae,
which are slightly shorter than the gut.
3. Epiploic appendages: peritoneum-covered sacs of
fat, attached in rows along the teniae.
 The taenia coli run the length of the large intestine.
Because the taenia coli are shorter than the large
bowel itself, the colon becomes sacculated, forming
the haustra of the colon which are the shelf-like
intraluminal projections

10. • The pattern of
haustrations and
the apearance
of mucosa help
in flexible
endoscopy
examination.
• Clinician will be
able to identify
the part of colon.

11. CEACUM
 Is the blind pouch of the large intestine. It
lies in the right iliac fossa and is usually
surrounded by peritoneum but has no
mesentery.
 Length : 6-7.5cm
 Width: 7.5cm
 Has two openings
 Ileal opening
 Appendix opening
(gerlach`s valve)

13. RELATION of CEACUM:
 Anteriorly: Coils of small intestine, sometimes
part of the greater omentum, and the anterior
abdominal wall in the right iliac region
 Posteriorly: The psoas and the iliacus muscles,
the femoral nerve, and the lateral cutaneous
nerve of the thigh. The appendix is commonly
found behind the cecum.
 Medially: The appendix arises from the cecum
on its medial side.

14. ILEOCAECAL JUNCTION
 Presents as transverse slit bounded by
upper and lower lips (projection of ileum
into cecum)
 At the edge the lips fuses with each other
and become continuous with folds of
mucous membrane called FRENULA.
 It act as physiological sphincter.

15. ASCENDING COLON
 is the first of four sections of the large
intestine.
 It is connected to the cecum below. The
ascending colon runs upwards through the
abdominal cavity toward the transverse
colon for approximately eight inches (15-
20 cm).
 Covered anteriorly, on either side by
peritoneum.

16. RELATIONS:
 ANTERIOR: anterior abdominal wall, hepatic
flexure of
colon, upper aspect of liver, gall
bladder and
Duodenum
 POSTERIOR:
Muscles: iliacus, quadratus lumborum (medially)
and transversus abdominis (laterally).
Nerves: lateral cutaneous nerve of thigh, ilio
inguinal nerve, ilio hypogastric nerve
Artery: iliac branch of iliolumbar artery

18. Lower
pole of R
kidney
Iliac crest
Lateral
border of
L-kidney

19. Taking into account all ages and sexes, colon cancer occurs
here most often (41%).

20. TRANSVERSE COLON
 The transverse colon is the part of the colon
from the hepatic flexure to the splenic flexure.
Is the longest subdivision.
 The transverse colon hangs off the stomach,
attached to it by a large fold of peritoneum
called the greater omentum.
 On the posterior side, the transverse colon is
connected to the posterior abdominal wall by a
mesentery known as the transverse
mesocolon.

21. The transverse colon is enclosed in
peritoneum, and is therefore mobile
RELATIONS:
 Anteriorly: The greater omentum and the
anterior abdominal wall (umbilical and
hypogastric regions)
 Posteriorly: The second part of the
duodenum, the head of the pancreas, and
the coils of the jejunum and the ileum

23. DESCENDING COLON
 The distal gut is the part of the colon from the
splenic flexure to the beginning of the sigmoid
colon.
 Upper end of splenic flexure is anchored to
diaphragm by phrenico-colic ligament.
 One function of the descending colon in the
digestive system is to store feces that will be
emptied into the rectum. It is retroperitoneal in
two-thirds of humans. In the other third, it has a
(usually short) mesentery.
 Gut flora are very dense in this region.
 Covered by peritoneum anteriorly, and on either
side.

24. RELATIONS:
 POSTERIOR: left kidney, left transverses
abdominis, left quadratus lumborum, left
iliacus, psoas major muscles.
And similar nerves and vessels in other side.
In male: lower part of descending colon lies
over external iliac artery, femoral nerve,
genitofemoral nerve and testicular vessels.
 ANTERIOR: Greater omentum, anterior
abdominal wall, coils of jejunum.

25. SIGMOID COLON
 The sigmoid colon is the part of the
large intestine after the descending
colon and before the rectum.
 It has its own mesentery. Which is v
shaped.
 Completely enclose in peritoneum.

26.  The name sigmoid means S-shaped. The
walls of the sigmoid colon are muscular, and
contract to increase the pressure inside the
colon, causing the stool to move into the
rectum.
 Sigmoidoscopy is a common diagnostic
technique used to examine the sigmoid
colon.

27. GROSS FEATURES
CECUM ASCEN.
COLON
TRANS.
COLON
DESC.
COLON
SIGMOI
D
COLON
6cm 20cm 38 cm 25 cm 25-38 cm
Intra
peritonea
l
retroperit
oneal
Intra
peritonea
l
retroperit
oneal
intraperit
oneal
No
mesentry
Short
mesentry
Has
mesentry
Short
mesentry
Largest
mesentry

30. BLOOD SUPPLY

31. ABDOMINAL ANGINA

32.  Abdominal angina is abdominal pain after eating that occurs
in individuals with ongoing poor blood supply to their small
intestines known as chronic mesenteric ischemia.
 when blood flow to the colon cannot increase enough to meet
visceral demands. This is similar to intermittent claudication in
peripheral vascular disease or angina pectoris in coronary
artery disease.
 Atherosclerotic disease is the most common cause of
abdominal angina. In most people, it is occlusion of the
superior mesenteric artery that is responsible for the
abdominal symptoms.
 Risk factors for superior mesenteric artery atherosclerosis
include smoking and hyperlipidemia

35. LYPHATIC DRAINAGE
 from the ascending colon and proximal
two-thirds of the transverse colon is to the
colic lymph nodes and the superior
mesenteric lymph nodes, which drain into
the cisterna chyli.
 The lymph from the distal one-third of the
transverse colon, the descending colon,
the sigmoid colon, and the upper rectum
drain into the inferior mesenteric and colic
lymph nodes.