CHAPTER 2
Stomach and duodenum: anatomy and structural anomalies

Erik C. von Rosenvinge^1,2 and Jean-Pierre Raufman^1,2

¹University of Maryland School of Medicine, Baltimore, MD, USA

²Veterans Affairs Maryland Health Care System, Baltimore, MD, USA

The anatomy of the stomach (Figure 2.1) and duodenum is intrinsically aligned with their functions. A thorough knowledge of the regional anatomy facilitates understanding of normal function as well as the pathophysiological mechanisms underlying disease. For example, a dense anastomotic network of arteries supplies oxygen to the stomach (Figure 2.2). Therefore, gastric ischemia is uncommon in the absence of surgical devascularization or severe systemic perturbations in blood flow. In addition, the stomach and duodenum are in close proximity to other vital abdominal organs such as the pancreas, liver, and biliary system. Cross‐sectional imaging, such as computed tomography (CT) scanning or magnetic resonance imaging (MRI) (Figures 2.3–2.6), demonstrate these anatomical relationships. Diseases of adjacent organs may affect the stomach and duodenum, but their proximity also permits exploitation of the stomach and duodenum as portals to access these structures for diagnostic and therapeutic purposes. Endoscopic ultrasonography (EUS) can be used to diagnose and treat gastric disorders (Figures 2.7 and 2.8). EUS can also be used to drain pancreatic cysts that impinge on the stomach and to biopsy pancreatic lesions and neighboring lymph nodes. Congenital or acquired pyloric stenosis (Figures 2.9 and 2.10), which narrow the gastric outlet, may result in abdominal distension, nausea, projectile vomiting, and dehydration. Treatment is by endoscopic dilation or surgery.

Esophagogastroduodenoscopy (EGD) remains the “gold standard” test to evaluate upper gastrointestinal disorders. EGD allows direct viewing of the mucosal surface, thereby facilitating diagnosis and treatment of inflammation, ulceration, neoplasia, and other conditions (Figures 2.11, 2.12, 2.13, and 2.14; see also Figures 2.7, 2.8, and 2.10). Endoscopic biopsy or excision of tissue allows for histological diagnosis of gastric and duodenal diseases. While radiological examinations, such as upper gastrointestinal series and small bowel follow‐through, have largely been supplanted by conventional and videocapsule endoscopy, radiology still plays a role in the diagnosis of selected gastrointestinal disorders, such as intestinal malrotation (Figure 2.15).