Dissection of jejunum, ileum and colon

Lymphatic structures, blood vessels and nerves of lower part of sigmoid colon, close-up view

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Image #144-4

Dissection of jejunum, ileum and colon

Lymphatic structures, blood vessels and nerves of lower part of sigmoid colon, close-up view

The sigmoid colon has been cut across at the point where it descends into the pelvic cavity. The peritoneal layers of its mesentery (21) have been separated to expose lymph nodes, lymphatic vessels and arteries as they approach the sigmoid colon. The superior rectal artery and vein (14,19) pass downward into the pelvis behind the sigmoid mesocolon.

1. Superior hypogastric plexus
2. Right common iliac artery
3. Iliac lymph node
4. Ileocolic artery
5. Ileal artery
6. Cut edge of peritoneum of root of mesenteries
7. Left common iliac vein
8. Position of Promontory of sacrum (covered by fascia)
9. Peritoneum overlying external iliac vessels
10. Sigmoid colon (cut across)
11. Pelvic cavity (pointer on pararectal fossa)
12. Rectum
13. Inferior mesenteric artery
14. Superior rectal artery
15. Sigmoid arteries
16. Psoas major muscle (covered by fascia)
17. Inferior mesenteric plexus
18. Position of ureter (visible as a vertically directed, cordlike structure covered by fascia)
19. Superior rectal vein
20. Upper pointer: Lymph node Lower pointer: Lymph vessel
21. Mesosigmoid colon (peritoneal layers spread apart)
22. Straight arteries
23. Cut margin of mesosigmoid colon
24. Appendices epiploicae