There are two types of hemorrhoids: External and Internal
External Hemorrhoids
External hemorrhoids are dilated blood vessels around the anus. They are called external because they are visible on physical examination as lumps at the anal verge. Severe pain develops when a blood clot forms within an external hemorrhoid resulting in a thrombosed hemorrhoid.
Internal Hemorrhoids
Internal hemorrhoids are dilated blood vessels inside the rectum. They are called internal because they are typically not seen on physical exam, unless they are prolapsing. Prolapsing hemorrhoids may develop when internal hemorrhoids are left untreated for a long time. Internal hemorrhoids, unlike external hemorrhoids, are painless because they are not supplied by sensitive nerve fibers.
The Four Grades of Internal Hemorrhoids
Internal hemorrhoids are divided into four grades depending on their degree of prolapse.
- Grade I: Grade I internal hemorrhoids do not protrude outside the anal canal. Grade I internal hemorrhoids are visualized using anoscopy or colonoscopy.
- Grade II: Grade II internal hemorrhoids prolapse outside the anal canal but reduce spontaneously.
- Grade III: Grade III internal hemorrhoids protrude outside the anal canal and require manual reduction.
- Grade IV: Grade IV internal hemorrhoids are constantly protruding outside the anal canal and cannot be reduced