13 The Colon
Anatomy
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)
Location
Cecum
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
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
Retroperitoneal.
Distal Rectum
Extraperitoneal.
Topograhic Relationships
Cecum
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
Attachments/Suspensions
turgor
organ pressure
Cecum
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.
Circulation
Arterial
superior mesenteric artery
inferior mesenteric artery
Venous
Portal vein.
Lymph Drainage
superior mesenteric lymph nodes
celiac lymph nodes
lumbar lymph nodes
inferior mesenteric lymph nodes
left lumbar lymphatic trunk
Innervation
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
Mobility
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.
Motility
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.
Physiology
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.
Pathologies
Symptoms that Require Medical Clarification
Signs of appendicitis on the right or left (diverticulitis)
Bloody stools
Change in bowel movements (longer than 3 weeks)
Appendicitis
Definition. Acute inflammation of the vermiform appendix with signs of an acute abdomen.
Causes. The cause is unknown.
Clinical.
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.
clinical
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
Clinical
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
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