→Ultimately, symptoms (shown in blue) occur. This happens when the order of events meets critical pathophysiological steps (shown in purple); the erosion of arterioles of the lamina propria of the anal nodule during passage of hard or diarrheal stool is typically responsible for the various forms of hemorrhoidal bleeding. Last, pain, a non-typical symptom of internal hemorrhoids, appears when complications (brown boxes) such as inflammation, incarceration, thrombosis and necrosis arise (based on references 4,7-11,13,15-17,19,2131,34,38,39) LP, lamina propria; MRV, middle rectal vein; SRV, superior rectal vein