13 The Colon


13 The Colon


General Facts

Length: approximately 1.5 m Diameter:

  • ascending colon 7-8cm

  • transverse colon 5 cm

  • descending colon 3-5cm

  • sigmoid colon 3-5cm

Significant angles:

  • hepatic flexure (right colic flexure)

  • splenic flexure (left colic flexure)

  • ileocecal valve

  • sigmoid angle

Special characteristics:

  • no villi and mucous membrane folds, only crypts

  • semilunar folds (contracted ring muscles, not constant)

  • haustra (noncontracted sections of the intestine)

  • taeniae coli (strong bands of longitudinal muscle, run together into a continuous muscle layer at the appendix and sigmoid)

  • epiploic appendices (small pouches of serosa filled with fat)



  • intraperitoneal

  • Runs diagonally in a caudal-medial-anterior direction and ends at the right iliac fossa.

  • approximately 7 cm long

  • The ileocecal valve is found on the left side (superior and slightly posterior).

Vermiform Appendix

  • 5-10cm long

  • variability in diverse locations

  • projection onto the wall of the torso: approximately 2 cm superior to McBurney point

Ascending Colon

  • retroperitoneal

  • pathway: on the right side in the lateral region superiorly and slightly posteriorly

Fig. 13.1 Location of the colon.

Right Colic Flexure

  • angle of 70-80°

  • oriented sagittally with the opening in an anteriorcaudal-medial direction

  • projection onto the wall of the torso: rib 10 anterior to the right

Transverse Colon

  • intraperitoneal

  • The left end lies higher than the right end.

  • Has a concave shape posteriorly.

  • Location is variable. We usually find it between two horizontal lines—one going through the ninth costal cartilage and the other through the navel—but it also extends to the lesser pelvis.

Left Colic Flexure

  • greater mobility than the right flexure

  • angle of 50°

  • frontosagittal orientation with the opening in an anteromedial direction

  • projection: eighth rib anterior to the left

Descending Colon

  • retroperitoneal

  • lies further posteriorly than the ascending colon in the lateral area on the left

Sigmoid Colon

  • intraperitoneal

  • Runs from the posterosuperior part of the iliac fossa along the outer edge of the left psoas, crosses it 3-4 cm in front of the inguinal ligament, enters the lesser pelvis, and ends at the height of S3 in the rectum.

  • Middle section can have a diameter of 15 cm.

  • Pelvic section of the sigmoid can be displaced upward by a full bladder, the rectum, its own state of fullness, or the uterus.

Proximal Rectum


Distal Rectum


Topograhic Relationships


  • abdominal wall

  • posterior peritoneum

  • iliac fascia

  • iliacus

  • envelope of the external iliac artery and vein

  • inguinal ligament

  • psoas major

  • lateral cutaneous nerve of the thigh

  • femoral nerve

  • genitofemoral nerve

  • small intestinal loops

Vermiform Appendix

  • right ovary

  • possible contact with the bladder, rectum, and uterus

Ascending Colon

  • iliac fossa

  • covered by peritoneum

  • right kidney

  • Toldt fascia

  • subcostal nerve

  • iliohypogastric nerve

  • ilioinguinal nerve

  • aponeurosis of quadratus lumborum, kidney fascia, iliac fascia

  • lateral and anterior abdominal wall

  • diaphragm

  • small intestinal loops

  • duodenum (descending part)

  • liver

  • rib 11

Right Colic Flexure

  • liver

  • duodenum (descending part)

  • diaphragm

  • right kidney

  • phrenicocolic ligament on the right

Transverse Colon

  • liver

  • gallbladder

  • abdominal wall indirectly via the greater omentum

  • greater curvature of the stomach

Transverse Mesocolon

  • pancreas

  • duodenum

  • jejunum

  • left kidney

  • spleen

Left Colic Flexure

  • greater curvature of the stomach

  • spleen

  • phrenicocolic ligament on the left

  • diaphragm

  • lateral abdominal wall

  • rib 8/9

Descending Colon

  • covered by peritoneum

  • left kidney

  • small intestinal loops

  • Toldt fascia

  • posterior abdominal wall

  • subcostal nerve

  • iliohypogastric nerve

  • ilioinguinal nerve

  • rib 10/11

Sigmoid Colon

  • iliac fascia

  • Toldt fascia

  • iliacus

  • small intestinal loops

  • lateral cutaneous nerve of the thigh

  • rectum

  • uterus

  • left ovary and fallopian tube

Sigmoid Mesocolon

  • left ureter

  • testicular/ovarian vessels on the left

  • external iliac vein


  • turgor

  • organ pressure


  • posterior peritoneum (superior part)

  • mesentery (inferior part)

Ascending Colon

  • peritoneum

  • Toldt fascia

Right Colic Flexure

  • peritoneum

  • phrenicocolic ligament

  • hepatocolic ligament (from the liver via the flexure to the right kidney)

  • cystoduodenal ligament (extension of the hepatoduodenal ligament)

Transverse Colon

  • transverse mesocolon

  • greater omentum (ends at the phrenicocolic ligaments)

  • gastrocolic ligament (part of the greater omentum): as a result of this ligament, the right part of the transverse colon has greater mobility

Left Colic Flexure

Phrenicocolic ligament.

Descending Colon

Toldt fascia.

Sigmoid Colon

Sigmoid mesocolon.



  • superior mesenteric artery

  • inferior mesenteric artery


Portal vein.

Lymph Drainage

  • superior mesenteric lymph nodes

  • celiac lymph nodes

  • lumbar lymph nodes

  • inferior mesenteric lymph nodes

  • left lumbar lymphatic trunk

Fig. 13.2 Attachments of the colon, schematic.
Fig. 13.3 Mesenteric attachments of the colon.


  • sympathetic nervous system from T10 to L2 via the greater and lesser splanchnic nerves

  • T10-T11 via the superior mesenteric ganglion

  • T12-L2 via the inferior mesenteric ganglion

  • parasympathetic nervous system

  • vagus nerve (ends at the superior mesenteric ganglion)

Sacral parasympathetic innervation from S2 to S4 via:

  • pelvic splanchnic nerves-inferior hypogastric plexushypogastric nerves

  • superior hypogastric plexus-inferior mesenteric plexus

Organ Clock

Maximal time: 5-7a.m.

Minimal time: 5-7p.m.

Organ-Tooth Interrelationship

For basic information, see page 34.

  • First molar in the lower jaw on the left for the left colon

  • First back tooth in the upper jaw on the left for the left colon

  • First back tooth in the upper jaw on the right for the right colon

Movement Physiology according to Barral


The greatest movement takes place in the flexures and in the transverse colon.

The diaphragm is the propelling force for the movement of the colic flexures: in the frontal plane, the diaphragmatic movement is greater on the side than in the center—the flexures move inferiorly and medially (approximately 3 cm in normal inhalations, up to 10cm in maximum inhalation).

In the sagittal plane, the flexures move anteroinferiorly.

The transverse colon also moves inferiorly in the frontal plane, whereby the following applies: the fuller it is, the higher it lies.


Each part of the colon completes a transversal motion on its parietal attachment (Toldt fascia, mesocolon). This results in a mediolateral or superoinferior (for the transverse colon) concave distortion in the frontal plane.

In the same way, a rotation takes place around the longitudinal axis of the colon.


In the colon, water and electrolytes are extracted from the chyme; the stool becomes thickened.

In addition, the feces can be stored in the sigmoid and rectum for several days.


Symptoms that Require Medical Clarification

  • Signs of appendicitis on the right or left (diverticulitis)

  • Bloody stools

  • Change in bowel movements (longer than 3 weeks)


Definition. Acute inflammation of the vermiform appendix with signs of an acute abdomen.

Causes. The cause is unknown.


  • pain that begins in the epigastrium, sometimes coliclike, and moves into the right lower abdomen in the course of hours

  • rectal-axillary temperature difference of more than 0.5°C in temperatures of about 38°C

  • pain at the McBurney point and Lanz point

  • rebound tenderness

  • Blumberg sign (crossed rebound tenderness)

  • Rovsing sign (retrograde compression of the colon)

  • positive psoas test on the right

  • Douglas pain

Ulcerative Colitis

Definition. Chronic inflammation of the large intestinal mucosa with ulcerations. The inflammation is limited to the mucosa and submucosa and spreads from the rectum proximally.

Causes. The cause is unknown. Possible causes include infections, and dietary, psychological, and immunological factors.

Familial aggregation occurs.


  • bloody/slimy diarrhea (guiding symptom)

  • The disease erupts in episodes with symptom-free intervals.

  • Depending on the severity of the disease, episodes can manifest with fever, abdominal spasms, and a definite feeling of sickness.

Irritable Bowel Syndrome

Definition. Functional intestinal disorder.

Causes. Psychological triggers.

Patients show the following characteristics:

  • lowered pain threshold for stretch reflexes

  • increased motor activity in the sigmoid colon

  • changed transit time of food

  • increased gas reflux in the stomach


  • sheep-dung or pencil-like stools

  • mucus in the stool (without blood)

  • diarrhea in the morning (the first stool is solid, the second soft, the third watery)

  • variable abdominal pain, mostly on the left side

  • food intolerances without proof of allergies

  • vegetative symptoms (headache, insomnia, dysuria)

  • overanxiousness

  • dysmenorrhea

  • carcinophobia

  • improvement of symptoms during vacations

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Jul 12, 2020 | Posted by in GASTROENTEROLOGY | Comments Off on 13 The Colon

Full access? Get Clinical Tree

Get Clinical Tree app for offline access