The document summarizes key details about the surgical anatomy of the large bowel and appendix. It discusses: 1) The lymphatic drainage patterns of different sections of the large bowel and how this informs the appropriate surgical resection for cancers in these areas. 2) The neural control of the gut wall, including sympathetic and parasympathetic innervation originating from different areas of the spinal cord and plexuses. 3) Hirschsprung's disease, where the absence of ganglion cells in a distal segment of the colon results in aganglionic megacolon, requiring resection within the ganglionated area.

1. SURGICAL ANATOMY OF LARGE BOWEL AND
APPENDIX

5. EXTERNAL FEATURES OF LARGE BOWEL
Teniae coli absent in appendix

14. EPICOLIC -> PARACOLIC-> MESOCOLIC
NODES

15. Resection of the large intestine should include the entire area served by a major artery as well as the lesion itself.
Most of the lymphatic drainage will be included.

16. • Because the ileocecal artery always arises from the superior mesenteric artery and lymph node metastases of cecum cancer
were limited to nodes along the ileocolic artery, cecum cancer can be cured by ileocecal resection.
• The right colic artery has various origins, and ascending colon cancer shows various patterns of lymph node metastases.
Therefore a right hemicolectomy should be performed for ascending colon cancer.
• The middle colic artery forks into right and left branches, and each branch has different branching variations. If the right colic
and middle colic arteries have a common trunk, a right hemicolectomy should be performed for transverse colon cancer on
the right side. If the left branch of the middle colic artery has an independent replaced origin, lymph node dissection should be
modified according to the variant origin. If the left colic artery and the first sigmoidal artery have a common trunk, the lymph
nodes along the common trunk should be removed for sigmoid colon cancer and for descending colon cancer.
• Of the patients with sigmoid colon cancer, 6.3% also had lymph node metastases along the superior rectal artery. Given that
the lymph nodes along the superior rectal artery are skeletonized, sigmoid colon cancer can be also cured by partial
sigmoidectomy

17. NEURAL CONTROL 0F GUT WALL

18. • Sympathetic Innervation
• The sympathetic supply to the right colon originates from the lower six thoracic segments of the spinal cord. Preganglionic fibers pass through the
sympathetic chain ganglia, then pass as thoracic splanchnic nerves to synapse in the celiac, aortic, and superior mesenteric plexuses. From the
plexuses, postganglionic fibers pass with the arteries in the mesentery to the small intestine and the right colon.
• On the left, preganglionic fibers arise from the first two (or three) lumbar segments of the cord, then travel as lumbar splanchnic nerves to the aortic
plexus and the inferior mesenteric plexus. From ganglia in this diffuse plexus, postganglionic fibers follow branches of the inferior mesenteric artery
to the left colon and the upper rectum.
• Parasympathetic Innervation
• Vagal fibers from the posterior trunk pass as the celiac division to and through the celiac ganglion without synapse. From the ganglion, preganglionic
fibers pass on the superior mesenteric artery to the small intestine and the right colon, where they synapse with ganglion cells of the intramural
plexuses.
• The left colon receives parasympathetic fibers from pelvic splanchnic nerves, which arise from the 2nd, 3rd, and 4th sacral nerves. These fibers
follow the course of the presacral nerve to reach the inferior mesenteric plexus. From this plexus, the preganglionic fibers follow the branches of the
inferior mesenteric artery to the left colon and the upper rectum

20. • The caliber of the large bowel is greater close to the cecum; it gradually gets smaller
toward the rectum, then dilates again at the rectal ampulla just above the surgical anal
canal
anterior cecal artery lies within
it

36. CLINICAL IMPORTANCE
• Congenital Aganglionic Megacolon (Hirschsprung's Disease)
• Aganglionic megacolon is the result of an absence of ganglion cells in a distal segment of colon.
• Neurenteric ganglion cells normally originate in the neural crest, enter the cranial end of the
esophagus, and then follow vagus nerve fibers caudally until the entire gut is innervated. Why the
migrating cells sometimes stop short of the rectum is unknown.
• The line of resection must be within the area in which ganglion cells are present. Because
aganglionosis is not the only cause of megacolon, a biopsy is necessary to demonstrate the
absence of ganglion cells in the narrowed segment and their presence in the dilated segment.

37. THANK YOU