removing rings prior to injecting . If a finger starts to swell with a ring in place , it can quickly obstruct the blood flow leading to loss of the finger . The artery that supplies blood to the finger lies just below the vein – if the artery is damaged the finger can die . The superficial veins of the hand tend to ‘ wobble ’ when people try to get a needle in them , and this can result in more frequent missed hits and vein damage .
Legs
The superficial leg veins are unlikely to be viable long-term prospects for injecting . The blood flow in these veins is slow , and if people inject too quickly there is often leakage into surrounding tissue . This can cause infection and further vein damage or it can cause the person to lose their dose . The legs contain many valves , which increases the likelihood of problems , as injecting at or around a valve causes more turbulence , and therefore clotting of the blood . This can damage the valve and further slow blood flow . The superficial veins of the leg tend to wobble ‘ when people try to get a needle in them , and this can result in more frequent missed hits ‘ and vein damage . As the flow of blood in the leg veins is upwards ( i . e . towards the heart ) it can be difficult to self inject in the correct direction in the legs , i . e . with the needle pointing up towards the top of the leg . Because these veins are furthest from the heart , and due to gravity , blood flow through the leg veins is slow . If drugs are injected too fast , the veins will be unable to cope with the extra fluid . When this happens , fluid can escape from the vein , around the needle , causing a miss .‘ Injecting slowly can reduce this . Healing of injection site damage and resistance to infection are less reliable because the blood flow is slow . Abscesses and other infections are therefore more possible for those injecting into their legs .
Varicose veins form , usually in the leg veins , because of damaged valves . The varicose vein has tight , thin walls and is often raised , stretching the skin . They should not be injected into , as they can bleed profusely because the damaged valves mean that blood can run back down the vein and out of the wound .
Feet