Any injury to a vein may be associated with considerable bleeding. There are a large number of veins and damage to veins, once the bleeding has been controlled, may present no clinical problems. The larger the vein, the more likely the patient is to suffer long term problems. Arterial injuries (page 113) are usually recognised early, and surgical repair is carried out. The importance of co-existing venous injuries has been recognised and primary surgical repair of the veins is now carried out, particularly when the injury includes a large vein (femoral vein, iliac vein, etc). Failure to recognise a coexisting venous injury may result in early failure of an arterial reconstruction for trauma. Veins are very thin-walled and extremely friable. A penetrating injury to a vein may result in a long laceration. Simple ligation of the vein may be adequate distally but, where the vein has a large diameter, repair should be carried out. Surgical repair of venous injury is technically more difficult than that of arterial injury. Blood tends to spurt from arterial injuries, and the source is quite obvious. The blood in the veins is at a low pressure and tends to well up, making it extremely difficult to identify the site of injury. Pressure on the vein above and below the site of injury accompanied by good suction to remove the blood will allow adequate visualisation. It may be possible to suture a vein to close a hole. It may be necessary to insert a patch or, in some instances, it may be necessary to replace a whole segment. By removing superficial veins (for example, the saphenous vein, if it is available), it is possible to make both the short segment graft and patches.