Inferior Mesenteric Plexus Flashcards

Explore the inferior mesenteric plexus, its sympathetic ganglia, lumbar splanchnic inputs, periarterial branches, and hindgut innervation.

Card 1 of 24Question

What is the inferior mesenteric plexus?

An autonomic nerve network surrounding the origin and branches of the inferior mesenteric artery.

In This Section

1. What is the inferior mesenteric plexus?

An autonomic nerve network surrounding the origin and branches of the inferior mesenteric artery.

2. Where is the inferior mesenteric plexus located?

In the retroperitoneum around the inferior mesenteric artery near its origin from the abdominal aorta.

3. At approximately which vertebral level does the inferior mesenteric artery arise?

L3.

4. Which sympathetic ganglia are associated with the inferior mesenteric plexus?

The inferior mesenteric ganglia, which may consist of one or more variable ganglionic masses.

5. How are the inferior mesenteric ganglia classified?

As prevertebral sympathetic ganglia.

6. Which nerves provide major preganglionic sympathetic contributions to the inferior mesenteric plexus?

The lumbar splanchnic nerves.

7. From which spinal cord region do sympathetic fibers supplying the inferior mesenteric plexus originate?

The lower thoracic and upper lumbar spinal cord, particularly around T12 to L2.

8. Which autonomic plexus connects superiorly with the inferior mesenteric plexus along the abdominal aorta?

The intermesenteric plexus, also called the abdominal aortic plexus in this region.

9. Which autonomic plexus is connected inferiorly with the inferior mesenteric plexus?

The superior hypogastric plexus through the lower abdominal aortic plexus.

10. Which embryological division of the gastrointestinal tract receives autonomic fibers through the inferior mesenteric plexus?

The hindgut.

11. Which portions of the colon receive autonomic fibers through the inferior mesenteric plexus?

The distal third of the transverse colon, descending colon, and sigmoid colon.

12. Which part of the rectum receives autonomic fibers through the superior rectal plexus?

The upper rectum.

13. Which periarterial plexus follows the left colic artery?

The left colic plexus.

14. Which branches of the inferior mesenteric plexus accompany the sigmoid arteries?

The sigmoid plexuses.

15. Which autonomic plexus accompanies the superior rectal artery?

The superior rectal plexus.

16. How do postganglionic sympathetic fibers from the inferior mesenteric ganglia reach the hindgut?

They travel along branches of the inferior mesenteric artery within periarterial plexuses.

17. Which nerves provide parasympathetic fibers to the inferior mesenteric plexus?

The pelvic splanchnic nerves arising from S2 to S4.

18. Through which pelvic autonomic network do parasympathetic fibers ascend toward the inferior mesenteric plexus?

The inferior hypogastric plexus and its connections with the hypogastric and abdominal aortic plexuses.

19. Do preganglionic parasympathetic fibers synapse in the inferior mesenteric ganglia?

No. They continue toward terminal or intramural ganglia in the hindgut.

20. What is the general effect of sympathetic stimulation through the inferior mesenteric plexus on colonic motility?

It decreases colonic motility and inhibits peristalsis.

21. How does sympathetic activity through the inferior mesenteric plexus affect colonic blood vessels?

It generally produces vasoconstriction of the vessels supplying the hindgut.

22. What is the general effect of pelvic parasympathetic stimulation on hindgut function?

It promotes colonic motility, peristalsis, and intestinal secretion.

23. Which visceral afferent fibers commonly accompany sympathetic pathways through the inferior mesenteric plexus?

Visceral pain afferents from hindgut structures, particularly those above the pelvic pain line.

24. Why is the inferior mesenteric plexus clinically important during left-sided colorectal surgery?

Dissection near the inferior mesenteric artery can injure autonomic fibers involved in distal colonic and pelvic visceral function.