Final answer:
A sigmoidoscopy is an examination that uses a sigmoidoscope to view the rectum and lower third of the colon. It is aimed at early identification of colorectal cancer, with a colonoscopy as a follow-up if necessary. The endoscope is the key device used for such internal examinations.
Step-by-step explanation:
The examination to view the lower portion of the sigmoid and rectum through a 10 to 12 inch scope is known as sigmoidoscopy. This procedure is different from a colonoscopy in that it only allows for the inspection of the rectum and the lower third of the colon, where most cases of colorectal cancer occur. A flexible sigmoidoscopy utilizes a small camera to visualize the interior of these sections without the need to examine the entire colon, unlike a colonoscopy which involves a full examination of the colon. In cases where polyps or potentially cancerous lesions are detected during a sigmoidoscopy, a follow-up colonoscopy is often required.
The rectum is the final section of the alimentary canal that stores feces before expulsion from the body. It is important for procedures like sigmoidoscopies, as it follows the curvature of the sacrum and contains internal transverse folds that help separate feces from gas. The term endoscope refers to the device used during these procedures, allowing doctors to view the interior of hollow organs or cavities using light transmitted through fiber bundles, with the ability to perform surgical procedures when necessary.