A patient in the emergency department sustained a knife wound to the abdomen. The wound extended through the membranes surrounding the large intestine, into the layers of the large intestine, and into the lumen of the large intestine. Discuss the

Question

membranes and layers that were penetrated, from superficial (outermost) to deep (innermost).

What will be an ideal response?

Answer 1

First, the wound penetrated through the membranes surrounding the large intestine which are the parietal peritoneum, and then the visceral peritoneum. The visceral peritoneum is often called the mesentery and is synonymous with the serosa (adventitia) layer of the alimentary canal organs. Next, the knife cut through the layers of the intestine, from muscularis externa, through the submucosa, and mucosa. The muscular externa consists of inner circular and outer longitudinal layers of smooth muscle. The submucosa is composed of dense irregular connective tissue with blood vessels, lymphatic vessels, submucosal glands, and the submucosal plexus. The most innermost layer is the mucosa which consists of three components: from outermost to innermost there are two thin layers of smooth muscle called the muscularis mucosae, and then a layer of loose connective tissue called the lamina propria, and finally a layer of epithelium facing the lumen.