Varicose veins – Symptoms and causes – Mayo Clinic

Varicose veins may be caused by weakened valves (incompetent valves) within the veins that allow blood to pool in your veins instead of traveling to your heart. Spider veins Open pop-up dialog box. Close. Spider veins. Spider veins. Spider veins appear as thin, red lines or as weblike networks of blood vessels on the surface of the skin. Spider …

https://www.mayoclinic.org/diseases-conditions/varicose-veins/symptoms-causes/syc-20350643