The protrusion of blood vessels is a manifestation of vasodilation, and the protruding blood vessels are usually veins. According to the part where the blood vessels protrude, the reason of protrusion is mainly divided into two kinds: 1, physiological performance: because the part where the protruding blood vessels are located, the skin is weak, the subcutaneous tissue is less, the position of blood vessels is very shallow, when exercising, drinking alcohol, emotional excitement or soaking in hot bath, the local blood filling, blood flow increases, causing blood vessel expansion, such as forehead, temple, back of foot, back of hand, breast, penis and other parts, these phenomena are 2.Pathological changes: The most common parts are veins of lower limbs and abdominal wall veins. When varicose veins appear in the veins of the lower extremities, the blood vessels will protrude obviously, which is due to the weakened elasticity of the blood vessels, valve insufficiency, and increased pressure in the veins of the lower extremities caused by blood regurgitation, resulting in the appearance of varicose veins in the lower extremities. The protrusion of varicose veins in the abdominal wall is also obvious due to compensatory hyperplasia of superficial abdominal wall veins mainly due to portal hypertension or vena cava obstruction. In case of vascular protrusion, it is recommended to visit a vascular surgery clinic to clarify the diagnosis and give symptomatic treatment under the guidance of a specialist.