Descending Colon

Question 1

Position

Answer 1

1. Extends down from left colic flexure to pelvic brim where it becomes continuous with pelvic colon
2. Lies in left hypochondrium, left lumbar, and left iliac regions

Question 2

Length

Answer 2

9-12 inches

Question 3

Peritoneal covering

Answer 3

1. Covered by peritoneum anterior and on sides
2. 2 paracolic gutters (longitudinal grooves) are found along its lateral and medial sides

Question 4

Left lateral gutter

Answer 4

1. Lateral to descending colon
2. Closed above by phrenicocolic ligament
3. Opens below into pelvic cavity

Question 5

Lateral medial gutter

Answer 5

1. Medial to descending colon
2. Closed above by left colic flexure
3. Open below into pelvic cavity

Question 6

Relations: anterior

Answer 6

1. Anterior abdominal wall
2. Greater omentum
3. Small intestine

Question 7

Relations: posterior

Answer 7

Like those of ascending colon but extend more upwards and downwards.
Bone:
1. Left iliac crest
Muscles:
1. Left Psoas major and minor
2. Left Iliacus
3. Left quadratus lumborum
4. Left transversus abdominis
Nerves:
1. Left genitofemoral
2. Left femoral
3. Left lateral cutaneous nerve thigh
4. Left Iliohypogastric
5. Left ilioinguinal
6. Left subcostal
Vessels:
1. Left external iliac
2. Left gonadal
3. Left subcostal
Left kidney

Question 8

Arterial supply

Answer 8

1. Superior left colic artery
2. Inferior left colic artery
   Into inferior mesenteric artery

Question 9

Venous drainage

Answer 9

1. Superior left colic vein
2. Inferior left colic vein
   Into inferior mesenteric vein (portal circulation)