A rectal speculum is a device that is inserted into the anus to keep the anus open for diagnostic viewing of the rectum or for anal surgery. The rectum is the last eight inches (20.3 cm) of the large intestine that culminates in an orifice called the anus. The rectum stores feces until it is ready to be excreted. Conditions that might warrant the use of a rectal speculum include detecting the presence of hemorrhoids, tumors, polyps, inflammation, intestinal bleeding, and anal fissures, conducting biopsies, and removing hemorrhoids. The speculum is typically a rigid tube or a set of blades that pushes the walls of the rectum apart so a physician can view the canal with direct vision.
Though speculums were traditionally made of metal, today many are made of plastic. Vaginal speculums may even be made of disposable plastic for one time use, allowing doctors to skip the step of thorough sterilization between uses. There is a higher risk of disposable plastic breaking in the rectum, however, so the speculum is typically still made of metal or a very tough plastic.
The word speculum is typically associated with the vaginal speculum, a device with two handles hinged to two rounded blades. This tool can sometimes be used as a rectal speculum as well. When closed, the blades resemble the shut bills of a bird’s beak. The physician lubricates the blades with a water-soluble jelly and inserts the speculum into the anus with the blades shut. As the physician cranks the handles shut, the bills of the speculum open, allowing him or her to see inside the body cavity.
The types and sizes of speculums may vary depending on the needs of the patient. A rectal speculum may have three blades to create a wider opening and clearer viewing. A colon exam called an anoscopy requires an anoscope, or a 3-4 inch (7.6-10.2 cm) rigid tube about the width of a typical bowel movement.
A proctoscope is similar, though it is usually made of metal, rather than a tough plastic, and is inserted deeper into the rectum. For even deeper viewing, such as during a colonoscopy, a physician may not be able to see the area with her bare eyes and choose to use an endoscope. An endoscope is a flexible tube with a lighted viewing mechanism at its end that sends images to a screen outside the body.
A typical examination using a speculum can be conducted in a doctor’s office. The patient will need to take off his underwear and assume a position that makes the anus accessible. The doctor may ask the patient to lie sideways, bend over the examining table, or sit on the table with knees tucked to the chest. Before inserting the speculum, it will be lubricated to prevent discomfort and the doctor may ask that the patient push as if trying to make a bowel movement and then sit at ease. The physician will then gently insert the speculum and shine a light into the tube to illuminate any fissures, or tears in the lining of the rectum, bulges, or other abnormalities. Often, the doctor can give the patient the results of the exam immediately.
A rectal speculum may also be used for hemorrhoid ligation. A hemorrhoid is a swollen vein in the rectum or anus. After the patient is locally anesthetized, the procedure begins by placing an anoscope or proctoscope in the rectum. The physician then places a tiny rubber band around the base of a hemorrhoid to cut off circulation. The hemorrhoid will eventually die and fall off, protecting the patient from pain, excessive bleeding, and clots.