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).

5–10cm long

variability in diverse locations

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

retroperitoneal

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

Fig. 13.1 Location of the colon.

angle of 70–80°

oriented sagittally with the opening in an anterior-caudal-medial direction

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

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.

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

retroperitoneal

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

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.

Retroperitoneal.

Extraperitoneal.

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

right ovary

possible contact with the bladder, rectum, and uterus

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

liver

duodenum (descending part)

diaphragm

right kidney

phrenicocolic ligament on the right

liver

gallbladder

abdominal wall indirectly via the greater omentum

greater curvature of the stomach

pancreas

duodenum

jejunum

left kidney

spleen

greater curvature of the stomach

spleen

phrenicocolic ligament on the left

diaphragm

lateral abdominal wall

rib 8/9

covered by peritoneum

left kidney

small intestinal loops

Toldt fascia

posterior abdominal wall

subcostal nerve

iliohypogastric nerve

ilioinguinal nerve

rib 10/11

iliac fascia

Toldt fascia

iliacus

small intestinal loops

lateral cutaneous nerve of the thigh

rectum

uterus

left ovary and fallopian tube

left ureter

testicular/ovarian vessels on the left

external iliac vein

turgor

organ pressure

posterior peritoneum (superior part)

mesentery (inferior part)

peritoneum

Toldt fascia

peritoneum

phrenicocolic ligament

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

cystoduodenal ligament (extension of the hepatoduodenal ligament)

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

Phrenicocolic ligament.

Toldt fascia.

Sigmoid mesocolon.

superior mesenteric artery

inferior mesenteric artery

Portal vein.

superior mesenteric lymph nodes

celiac lymph nodes

lumbar lymph nodes

inferior mesenteric lymph nodes

left lumbar lymphatic trunk

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

Maximal time: 5–7a.m.

Minimal time: 5–7p.m.

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.