67 a and a pair of markers 67 b are provided to indicate the measurement on the graduated rule 65 shown through the window 67 a the bore 64 can be defined into two portions a front portion 64 a and a back portion 64 b the front portion 64 a is where an elongated member such as a k wire is received for measurement and the inside diameter of the front portion 64 a is appropriately matched to the diameter of the intended elongated member the back portion 64 b is where the elastically compressible member 70 and the piston 72 reside thus the inside diameter of the back portion 64 b is appropriately matched to the diameter of the elastically compressible member 70 and the piston 72 where the diameter of the elastically compressible member 70 and the piston 72 are larger than the diameter of the front portion 64 a the inside diameter of the back portion 64 b will be larger and there will be a transition portion 64 c where the diameters change see fig1 d the transition portion 64 c can act as a stop for the piston 72 defining its resting position as discussed above during the description of the surgical procedures after a k wire is drilled into a bone to a certain depth using the drill guide the depth gage 60 can be used to measure the length of the k wire that is inside the bone this measurement is necessary to determine the proper length of a bone screw that will be used after the k.