4. Many spring activated finger stick devices come with two rigid plastic covers for the end that touches your finger. Usually one cover is for thin or soft skin (as in small children), while the other is for thick or callused skin. To get a shallower puncture, use the thicker tipped cover; to get a deeper puncture, use the thinner tipped cover. An even deeper puncture may be obtained by strongly pressing your finger against the lancet cover. A very shallow puncture may be obtained by barely touching the fingertip to the cover. The pressure of the finger on the cover determines how deep the puncture will go. It should be deep enough to provide an adequate drop of blood, but not be so deep as to cause bruising or pain. Contrary to common teaching, the best sites for pricking fingers are actually on the back of the hand. Prick your finger between the first joint and the nail, or between the first and second joints (not over the knuckles), as shown by the shaded areas in Figure 4-1. Pricking these sites should be less likely to cause pain and more likely to produce a drop of blood than will pricking your fingers on the palmar side of the hand. You will also be free from the calluses that occur after repeated punctures on the palmar surface of the fingers.* When using this technique, I press the tip of the lancing device very gently against the finger, as the skin is thinner there than on the palmar surface. If you find it repugnant to prick the dorsum (knuckle side) of your fingers, use the sites on the palmar surface illustrated in Figure 4-2. Personally, I actually use all of the sites shown in both diagrams. As you will not be sharing your finger stick device, you need not discard the disposable plastic lancets with the metal point after every finger stick. It is a good idea to discard them once a month, as they do eventually become dull.