Rectal hemorrhage refers to bleeding in the rectum

Rectum

The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...

. There are many causes of rectal hemorrhage, including hemorrhoids (which are dilated vessels in the perianal fat pads), rectal varices, proctitis

Proctitis

Proctitis is an inflammation of the anus and the lining of the rectum, affecting only the last 6 inches of the rectum.-Overview:Symptoms are ineffectual straining to empty the bowels, diarrhea, rectal bleeding and possible discharge, a feeling of not having adequately emptied the bowels,...

 (of various causes), stercal ulcers and infections. Diagnosis is usually made by proctoscopy

Proctoscopy

Proctoscopy is a common medical procedure in which an instrument called a proctoscope is used to examine the anal cavity, rectum or sigmoid colon. A proctoscope is a short, straight, rigid, hollow metal tube, and usually has a small light bulb mounted at the end...

, which is an endoscopic

Endoscopy

Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an endoscope , an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ...

 test.

Bleeding from the anus

Anus

The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...

is termed anal hemorrhage and is usually superficial in nature.