Colon Rectum Anal Canal

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ColonRectum Anal Canal

• Sonal Tripathi

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Large vs Small Intestines

• Omental Appendices
• Teniae Coli
• Haustra
• Wider than small intestine

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Arterial Supply- Ileocolic branches of
SMANerves- Superior mesenteric plexus Vagus
nerve Sympathetic fibres from lower
thoracic Afferent fibres of appendix accompany
symp fibres to T10

• Appendix

• Caecum

• Vermiform
• Contains masses of lymphoid tissue
• Arises from inferior to ileocecal junction
• Variable position (usually retrocecal)

• First part
• Lies in right iliac fossa, within 2.5cm of
  inguinal ligament
• Blind intestinal pouch, no mesentery

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Appendicitis

• Severe pain in RIF
• May begin in the periumbilical region...why?
• Causes?
• Examination
• Pressure over Mc Burneys point, why?
• Complications
• Ischaemia, gangrene, rupture of inflamed appendix
  gt peritonitis
• Treatment
• Surgery (open or laparoscopic)

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Colon

• Ascending colon
• Retroperitoneal
• From caecum to R.lobe of liver (Hepatic flexure)
• Transverse colon
• Hepatic flexure to splenic flexure
• Splenic flexure less mobile, anterior to inferior
  left kidney, attached to diaphragm via
  phrenicocolic ligament
• Attached by mesocolon
• Divides cavity into supracolic and infracolic
  compartments

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Colon

• Descending colon
• Retroperitoneal
• From splenic flexure to sigmoid
• Passes anterior to lateral border of left kidney
• Sigmoid colon
• S-shaped loop, variable length
• Links descending colon (iliac fossa) and rectum
  (S3 vertebra)
• Rectosigmoid junction
• Termination of taeniae coli
• Long mesentery gt volvulus
• Left ureter and division of left common iliac
  artery
• Retroperitoneal, posterior to root of sigmoid

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Nerves and Vasculature

• Ascending colon
• SMA ileocolic and right colic arteries
• SMV ileocolic and right colic veins
• Superior mesenteric nerve plexus
• Transverse colon
• SMA middle colic artery /- RL colic arteries
• SMV
• Superior mesenteric nerve plexus

• Descending and sigmoid colon
• IMA left colic and sigmoid arteries
• IMV gt splenic vein gt hepatic portal vein
• Symp. Nerves abdominopelvic splanchnic nerves,
  superior mesenteric plexus
• Parasymp. Nerves pelvic splanchnic nerves via
  pelvic plexus

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Volvulus

• Mobile ascending colon/ caecum
• Sigmoid colon
• Obstructive signs and symptoms
• Constipation
• Ischaemia
• Faecal compaction
• Necrosis
• Complications
• Perforation
• Fatal peritonitis

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Diverticulosis

• Multiple out-pocketings of mucosa of colon
• Middle aged/ elderly affected
• Diverticular disease
• Symptomatic diverticula
• Diverticulitis
• Inflammation of a diverticulum
• Colonic diverticula
• Mucosa protrudes through weak points between
  muscle fibres, where nutrient arteries perforate
  the muscle coat

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• Complications
• Diverticulitis altered bowel habit, left sided
  colic relieved by defecation/flatulence, pyrexia,
  tenderness
• Perforation ileus, peritonitis, shock
• Haemmorhage
• Fistulae enterocolic, colovaginal, colovesical
• Abscesses
• Post-infective strictures

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Colitis

• Chronic inflammation of colon
• Ulcerative diffuse infl of the mucosa- can
  spread to entire colon- ulcer, polyp formation,
  diarrhoea with blood or mucous- anaemia
• Crohns disease can be from mouth to anus-
  spreads to entire thickness of tract- can have
  skip lesions-
• Management
• Medication
• Surgical- colectomy /- stoma

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Rectum

• Lies in the pelvis
• From sigmoid colon (rectosigmoid junction S3) to
  anal canal (coccyx)
• Flexures
• Sacral
• Anorectal
• Lateral (superior, inferior and intermediate)
• Peritoneum reflections
• Males rectum to posterior bladder gt
  rectovesical pouch
• Females rectum to posterior vagina
  gtrectouterine pouch
• Lateral, pararectal fossae- allow rectum to
  distend as fills with faeces

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Anal Canal

• Begins at end of rectum where puborectalis muscle
  narrows the ampulla
• Internal/external anal sphincters
• Pectinate line
• Above Visceral, columnar epithelium Anal columns
• Below Somatic, stratified sq. Epithelium, Anal
  valves and sinuses
• Differences in blood and nerve supply

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Nerves and Vasculature

• Rectum and Anal Canal
• Proximal part gt IMA (superior rectal artery)
• Middle and inferior gt Internal iliac arteries
  (middle rectal arteries)
• Anorectal junction and canal gt Internal pudendal
  arteries (inferior rectal arteries)..below the
  pectinate
• Arteries drain into the superior (portal venous),
  middle and inferior rectal veins (systemic
  venous)
• Symp innervation lumbar spinal cord
• Lumbar splanchnic and hypogastric/pelvic plexuses
• Parasymp S2-S4
• Pelvic splanchnic and inferior hypogastric

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• Rectal Examination
• Prostrate, seminal glands, cervix, sacrum,
  coccyx, ischial spines and tuberosities can be
  palpated among other things
• Can also be used to look for malena and
  constipation
• Colorectal Cancer
• Bleeding, mucous, altered bowel habit
• Surgical resection can be done depending on site
  of tumour
• Ano-rectal varices
• In portal hypertension at site of anastomoses
  between portal and systemic veins
• Haemmorhoids
• Dilations of submucosal veins bulging into lumen
  of canal
• Internal above pectinate line, can be ligated
• External painful as somatic supply, can prolapse
  into anus

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Thanks for listening Questions?