Sigmoid Colon

Question 0

Between descending colon and rectum

Begins at S1 (sacral promontory, pelvic inlet) & ends at S3 (rectosigmoid junction), where taenia coli are replaced by circular later of smooth muscle

Intraperitoneal, suspended by sigmoid mesocolon
- L ureter & L common iliac artery at the apex of sigmoid mesocolon

Blood supply: sigmoid arteries & rectosigmoid artery

Venous drainage: sigmoid vein –> inferior mesenteric vein –> hepatic portal system

Answer 0

Sigmoid colon

Question 1

Aganglionic megacolon

Absence of neural crest cells in myenteric plexus

Absence of peristalsis, fecal retention, abdominal distention

Answer 1

Hirchsprung’s disease

Question 2

Presence of diverticula (pouches or sacs)

MC: sigmoid colon

> 60 year old, low fiber, western diet

Perforation/inflammation of diverticula –> diverticulitis

Answer 2

Diverticulosis

Question 3

Examination of sigmoid colon & rectum

At rectosigmoid junction, the sigmoid colon bends in anterior direction & to the left

Answer 3

Flexible sigmoidoscopy

Question 4

Sigmoid colon is often used because of its mobility

May ablate the pelvic nerve plexus –> loss of ejaculation, erection, urine retention, ⬇️ peristalsis in the remaining colon

Answer 4

Colostomy