protrusion from or a depression in surface 80 of implantable medical device 12 although the location of implantable medical device 12 typically may be identified following implantable due to the general shallowness of the implant location determining the location of implantable medical device 12 does not necessarily translate to knowing the location of secondary coil 26 as can be seen in fig1 secondary coil 26 may be located off center i e not centered on surface 80 of implantable medical device fig1 provides a cross sectional side view of implantable medical device 12 implanted under cutaneous boundary 44 mating element 82 in this embodiment illustrated as a depression is positioned in a predetermined relationship with secondary coil 26 in this embodiment mating element 92 is co aligned with the axis of secondary coil 26 external power source 24 has a complementary mating element 84 in this embodiment illustrated as a projection positioned in a predetermined relationship with primary coil 34 in this embodiment mating element 84 is co aligned with the axis of primary coil 34 when transcutaneous energy transfer is desired to be initiated such as for charging a rechargeable power source in implantable medical device 12 external power source 12 or typically an antenna associated with external power source 12 containing mating element 84 is placed on or near transcutaneous boundary 44 near the location of implantable medical device 12 such location can be generally determined by tactilely sensing a protrusion or bump that implantable medical device 12 makes in cutaneous boundary 44 due to the shallowness of the implant location however merely placing external power source 24 in the vicinity of implantable medical device 12 does not necessarily mean that primary coil 34 and secondary coil 26 are aligned proper alignment of primary coil 34 and.