system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Referred pain in external hemorrhoids is due to
assistant
The correct answer is  Internal hemorrhoids are located on the inside lining of the rectum and cannot be felt unless they prolapse and push through the anus opening causing pain and itching. A thrombosed external hemorrhoid occurs when blood within the blood vessel clots, and may cause significant pain and swelling.