Diverticulosis of the Small Intestine

Acquired diverticula of the small bowel are usually multiple and are practically limited to the upper part of the jejunum.3 Examination of a specimen (Fig. 14-14a) documents that the diverticula do not arise randomly from the circumference of the small intestine but are strikingly situated at or immediately alongside the mes-

Table 14—1 Pathologic localization

Sole or predominant border of small bowel involved

Diseases Mesenteric Antimesenteric

Diverticulosis

Meckel's diverticulum

Scleroderma

Intestinal duplication

Seeded, metastases

Hematogenous metastases

Carcinoid tumors

Desmoplastic mesenteric mass

Multiple carcinoids

Regional enteritis

Rigidity, ulcerations,

sinus tracts

Pseudosacculations

CT comb sign

Lymphoma

Bleeding

Intramural thumbprints

Postfibrotic pseu do diverticula

Diverticulosis Small Intestine

Fig. 14—14. Gross specimen of diverticulosis of the jejunum.

(a) The loop is opened by cutting along the antimesenteric border. The multiple diverticula arise in a row distinctly from the mesenteric borders, invaginating between the leaves of the mesentery.

(b) Viewed from the mucosal aspect, the elliptical orifices extend along the line of attachment of the mesentery.

(Reproduced from Meyers.2)

enteric border, pushing their way between the leaves of the mesentery. The long axis of their domes, as well as of their elliptical orifices (Fig. 14-14b), tends to parallel the longitudinal axis of the bowel. Such diverticula of the small intestine are of the "pulsion" mucous membrane type. They arise in relation to the sites of penetration of the bowel wall by the vasa recta, which enter on the mesenteric border.4

This precise localization of small bowel diverticula to the mesenteric border can be identified radiologically in 75% of cases.2 The saccules usually are amorphous, without a mucosal pattern, and characteristically extend from the concave (mesenteric) margins of jejunal loops curved away from the axis of the root of the mesentery (Figs. 14-15 and 14-16). Diverticula of the terminal ileum also follow this pattern (Fig. 14-17).

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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