During a colonoscopy, the physician inserts a thin scope into the rectum to see images of the colon, according to WebMD. The colonoscope is about 1/2 inch in diameter and is flexible so it bends and follows the curves of the colon.
Preparation for a colonoscopy involves a special diet and medications with specific instructions leading up to the procedure to ensure the patient has empty bowels, notes Cleveland Clinic. An empty bowel ensures the physician gets a clear image of the colon. At the appointment, the patient dresses in a hospital gown and gets an IV. Medication administered through the IV causes the patient to relax and feel drowsy without completely losing consciousness.
The patient lies on her side with her knees toward her chest, states Cleveland Clinic. The colonoscope blows a small amount of air into the colon so the physician has a better view of the walls. The physician moves the scope slowly through the colon. The physician may take a biopsy of any abnormal areas during the colonoscopy for analysis.
The colonoscopy procedure typically lasts between 30 and 60 minutes, says WebMD. Patients sometimes feel cramping during the procedure. Cramping or the sensation of having gas sometimes lasts for a brief period after the colonoscopy. The patient typically waits in the room for 30 minutes after the procedure for observation.