Vessels and nerves of the hindgut (Dave's notes)

Question 1

What is the blood supply of the hindgut and at what level does this arise?

Answer 1

The IMA

which arises at L3 the (level of the umbilicus)

Question 2

What are the boundaries of the IMA supply?

Answer 2

Distal 1/3 transverse colon to the rectum

Question 3

Describe the course of the IMA

Answer 3

The IMA runs obliquely down in the left infracolic compartment to the pelvic brim (retroperitoneal structure)

It crosses the pelvic brim at the bifurcation of the left common iliac vessels over the SI joint, then converges with the ureter

Question 4

What significant structures does the IMA cross?

Answer 4

• Lies on the aorta
• crosses the left psoas
• left common iliac artery
• left hypogastric nerve

Question 5

What are the terminal branches of the IMA?

Answer 5

The superior rectal artery

Question 6

At what level does the IMA become the superior rectal artery?

Answer 6

At the pelvic brim S3

(splits into 2 terminal br supplying each side of the rectum)

Question 7

Does the IMA cross the left ureter?

Answer 7

No but all of its branches do

Question 8

What is the course of the left colic artery?

Answer 8

• Arise from IMA
• travels anterior to the psoas major muscle, left ureter and left internal spermatic vessels,
• then divide into ascending and descending br

ascending br
- cross left kidney anteriorly
- enter mesentry of the transverse colon and moves superiorly

descending br
- moves inferiorly to supply lower part of descending colon
- anastomose with superior sigmoid artery.

Question 9

The sigmoid arteries are …….. to …….. branches forming ……………. ………..

Answer 9

2 to 4 branches forming anastomotic loops

Question 10

Describe the venous drainage of the hindgut

Answer 10

The superior rectal vein runs up in the root of the sigmoid mesocolon (to the left of the artery) and becomes the IMV. The IMV receives tributaries identical to the arterial branches but runs some distance to the left of the artery.

Question 11

What occurs to the IMV at the DJ flexure?

Answer 11

The IMV arches right raising a ridge and creating the paraduodenal recess.

Question 12

What is the course of the IMV from the point of the ridge it forms at the DJ flexure?

Answer 12

The IMV passes along the lower border of the pancreas in front of ?the left renal vein to enter into the splenic vein (but may enter into the SMV).