A device for determining the depth of an incision from the epidermal layer to a puncture in a blood vessel in which the device includes an elongated member which has a lumen extending from a distal end to a proximal end. The distal end of the elongated member is configured to locate the blood vessel....http://www.google.com/patents/US7201725?utm_source=gb-gplus-sharePatent US7201725 - Device and method for determining a depth of an incision
