Hemorrhoids, commonly referred to as piles, are a widespread condition involving the swelling of vascular structures located in the anal canal. These structures are natural cushions of blood vessels and tissue that assist in stool control. When they become enlarged, inflamed, or displaced, they are classified as a disease. Internal hemorrhoids develop high up inside the rectum, which dictates their physical appearance and the patient’s experience of the condition.
The Location and Nature of Internal Hemorrhoids
Internal hemorrhoids are anatomically defined by their position above a landmark in the anal canal called the dentate line. This line marks the transition point between the sensitive, nerve-rich skin of the outer anus and the moist, insensitive lining of the upper anal canal. Because they originate in this higher region, internal hemorrhoids are covered by the columnar epithelium, a type of mucous membrane. This mucosal covering lacks the nerve fibers that sense pain, explaining why early-stage internal hemorrhoids typically cause little discomfort.
The hemorrhoids themselves are essentially engorged vascular cushions. When the surrounding supportive tissue weakens, the vascular cushions can slide downward and swell due to increased pressure. This anatomical placement above the dentate line is the reason they are not usually visible or palpable to the average person.
Visual Appearance When Not Prolapsed
In their earliest stages, internal hemorrhoids are hidden from external view, making it impossible for a patient to observe them without specialized tools. A medical professional must use an instrument like an anoscope or proctoscope to visualize the tissue within the anal canal. When viewed in this manner, the hemorrhoids appear as distinct, enlarged cushions projecting into the anal canal lumen.
These cushions are typically soft, dark-colored, often purplish or deep red, hemispherical masses. Their color comes from the engorged blood vessels, and their texture is soft because they are covered by the moist, delicate mucous membrane of the rectum. This in-situ appearance corresponds to what is medically known as a Grade I internal hemorrhoid.
Understanding Prolapse and Grading
The process of prolapse, where the internal hemorrhoid pushes out of the anal opening, causes the most dramatic change in appearance and is classified into four distinct grades:
- Grade I: Remains entirely within the anal canal and is invisible externally.
- Grade II: Prolapses during a bowel movement or straining, but quickly and spontaneously retracts back inside once the straining stops.
- Grade III: Protrudes outside the anal verge during defecation and requires the patient to manually push it back into the anal canal.
- Grade IV: Is permanently prolapsed and cannot be manually reduced, presenting as a constant, sizable mass of tissue outside the anal opening.
A Grade IV hemorrhoid can become acutely painful if the prolapsed tissue becomes strangulated or thrombosed, meaning a blood clot forms within it. In this scenario, the mass will appear as a firm, often dark red or bluish lump due to the trapped, clotted blood and lack of proper circulation.
Key Symptoms That Indicate Internal Hemorrhoids
Since internal hemorrhoids often begin without any visible external signs, the primary indicator of their presence is typically the non-visual symptom of painless rectal bleeding. This bleeding is characteristically bright red because it originates from the arterial blood in the upper anal canal. The blood may be noticed as streaks on the surface of the stool, on the toilet paper after wiping, or as drips into the toilet bowl after a bowel movement.
The hemorrhoid itself can also cause a slimy mucus discharge, which can lead to localized itching and irritation around the external skin of the anus. Patients may also experience a sensation of incomplete evacuation. Discomfort only arises when the prolapsed tissue is severely irritated, becomes strangulated, or develops a clot.