Spider Veins – also known as broken capillaries, can occur on any area of the body. These tiny, red, web-shaped lines are common on the legs and are entirely harmless. Broken capillaries occur when blood pools inside your veins, causing the vein to bulge and eventually branch out. This branch is what we refer to as a spider vein. Sun exposure and ultraviolet light are the primary causes of this condition, along with high blood pressure, rosacea, and other cardiovascular health conditions.