The essential defect when a vein becomes varicose is a breakdown in this valve system — not only in the superficial veins but also in the communicating channels between the deep and the superficial veins.
This vein, then, becomes distended with blood and becomes lengthened and tortuous.
Those small dilated veins which may appear on the thigh or on the foot are not varicose and are not amenable to treatment.
Prolonged standing and the wearing of tight garters or underclothes, especially the panty-girdle, all contribute to the formation of varicose veins.
As well, there is an heredity factor, with some people having an inbuilt weakness in the vein and its valves.
When the pressure inside the abdomen is raised, such as with pregnancy, the enlarged womb may press on the abdominal veins and lead to varicosities in the leg.
Apart from their appearance, varicose veins may cause aching in the legs and, eventually, because of the pressure effect, pigmentation and thinning of the skin in the lower leg.