i am but a baby in the violin world, but i am a master craftsman, and there is nothing in this world that i cannot build. wood, stone, metals, plastics, the materials makes no difference, with enough horsepower or manpower i have the skills to manufacture anything, passed down from generation to generation for the last 220 years. 1 month ago out of no where i woke with the idea of building a violin a violin, every since then the idea has consumed me...so now i study, read books, and have involved 100's of hours of research before picking up the first tool, still i have many questions, probably it will be  6 months or even longer before i start, i have to know everything, density of the wood, height and length of the curvatures, thickness and wood pretreatment, it has to be perfect.....but i keep running up on several x-rays that have a 6-8mm spine running down the length of the body on the inside of the instrument. mostly it runs under the G-string, but i have rarely seen it under the E-string,...someone please explain what this is and what it does, i need to know everything about this.. it looks like a piece carved from the bottom side of the top cover, down the length, maybe because the top is thin it needs rigidity??? please i need any and all input...thank-you ......here are some examples                                                                                                                                                                                                             https://plus.google.com/110032.....0010346386                                                                                                                                             http://www.aviolin.com/blog/ct.....n-xray.JPG                                                                                                                                  http://archivesmusee.citedelam.....face.jpg                                                      http://www.engineering.com/por...../Viol1.jpg