Final answer:
The supine position is the ideal position for a patient to demonstrate esophageal varices during an endoscopic examination.
Step-by-step explanation:
To demonstrate esophageal varices, the ideal position for a patient when undergoing an endoscopic examination is supine, as this allows the gastroenterologist to best visualize the structures within the upper gastrointestinal tract. In the supine position, the patient lies on their back with their upper limbs, including the palms, touching the sides of their body, and the lower limbs touching at the sides. This positioning is often used during an endoscopic procedure such as an upper GI endoscopy or an endoscopic ultrasound, as it gives the endoscopist the most stable and controlled environment to observe internal structures, including any varices that may be present.