Small and Large Intestine



Small and Large Intestine






OMENTUM (OMENTAL MOBILIZATION, OMENTECTOMY)


INCISION

Beginning at the xiphoid process, make a full-thickness bilateral subcostal incision through all abdominal wall layers. Use the mid- or posterior axillary line to continue incising the abdominal wall down to the pelvis. Carry this incision anteriorly over the anterior iliac crest. Do not disrupt the inguinal regions. Now lift the anterior abdominal wall. Note that the falciform and round ligaments will have to be divided. The entire anterior abdominal wall can then be flipped caudally onto the thighs to reveal the abdominal contents (see Chapter 3, “Thorax” for chest wall mobilization to facilitate the abdominal sections.) (Fig. 5.1).



CLINICAL HIGHLIGHTS



  • The blood supply to the omentum comes from both the right and left gastroepiploic arteries. The omentum can be mobilized from the left side of the abdomen or from the right side of the abdomen.







    Figure 5.2 Blood supply to the stomach and omentum.


  • The anastomosis between right and left gastroepiploic arteries is attenuated, commonly absent (see Fig. 5.2). However, a rich crossover vascular network between the right and left is present in the body of the omentum.


  • Preserving gastroepiploic blood supply to the omentum allows it to be used as a wrap. Omental reinforcement of anastomoses has been described in many areas of the body. However, the length necessary to reach these areas is attained by understanding how to mobilize a viable omental pedicle as you have done in this dissection.


  • The left gastroepiploic artery arises from the splenic artery and travels in the presplenic fold making it difficult to identify (see Fig. 5.2).


APPENDIX (APPENDECTOMY)


INCISION

An often used incision for appendectomy is a transverse Rocky-Davis incision situated at the lateral border of the rectus muscle transversely between the iliac crest and the umbilicus (Fig. 5.3). The internal oblique and
transversus muscles are split in line with their fibers. The peritoneum is opened and retracted to gain access to the inflamed appendix.






Figure 5.3 Appendectomy, Rocky-Davis incision.



CLINICAL HIGHLIGHTS



  • The ileal fat pad is a consistent anatomic marker, which is very useful in the inflamed right lower quadrant. Use it to orient yourself and to find the appendix. It will reliably lead you down to the appendix even if other landmarks are obscured by inflammation or abscess formation.


  • Inversion of the base of the appendix is optional. If you do, a “Z” stitch may be easier to use than a purse string seromuscular stitch.



RIGHT COLON (RIGHT HEMICOLECTOMY)


INCISION

Refer to Omentum procedure.



CLINICAL HIGHLIGHTS



  • Note the common blood supply to the terminal ileum and the cecum. To perform a right hemicolectomy, be sure to trace the colonic branches back to the main trunk of the ileocolic artery coming from the SMA. Do not ligate the SMA (see Fig. 5.10).


  • While mobilizing the posterior areolar attachments of the colon, note the proximity to the right kidney and duodenum. A tumor of the ascending colon may have local extension into the duodenum or right kidney. Oncologic resection will entail resection of these structures en bloc if invaded by tumor (see Fig. 5.8).






    Figure 5.10 Right hemicolectomy resection margins depend on tumor position and blood supply.

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    Oct 16, 2018 | Posted by in ANATOMY | Comments Off on Small and Large Intestine
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