5 INSERTING THE CANNULA INTO A HAND VEIN Before performing venipuncture, stretch and immobilize the vein as shown earlier. Press the vein lightly to check for rebound elasticity and to get a sense of its depth and resilience Palpate the portion where the cannula tip will rest, not the point where you intend to insert the cannula. If you touch the insertion site, you'll have to reclean the skin. To insert the cannula into a hand vein, follow the steps shown here.