|Since full color was not essential for this project, Gary opted for the Makerbot Replicator which prints objects using a plastic material. “The plastic material is a little easier to clean and tends to be more durable, so I felt it would hold up better when assembling and disassembling the femur segments.” Pleased with the initial results, Professor Snyder began to envision other ways the printouts could be useful as teaching aids. For example, could they show pathological variations in how the femur articulates with the pelvis through the ball and socket joint?|
Femur printout before and after assembly
Original femur bone (top) and printed replica
Dr. Steve Snyder knows can tell you all about the latest digital apps for studying human anatomy. An avid user of 3D4Medical, Professor Snyder has used their Complete Medical Lab to develop custom lecture presentations, lab demonstrations, and virtual study aids for his Anatomy I and II students. Still there is nothing quite like the look and feel of an actual human bone for illustrating important anatomical concepts. [Quote from Dr. Snyder] Which is why back in Spring of 2016, Snyder approached the Instructional Technology & Distributed Learning group with an initial list of his needs for 3D skeletal printouts. They included scaled up versions of the cervical vertebrae, reproductions of a human femur, and 3 anatomical variations of the scapula. Following the initial meeting with ITDL Manager Miary Andriamiarisoa and selected ITDL staff, 3D Visualization Specialist Gary Wisser was assigned to the project. Gary’s first task was to print out a replica of the femur, which at 17 inches, was too large to print as one piece using either the Makerbot Replicator or Mcor Iris 3D printer. Now he had to get creative. “I knew it was possible to scan the entire bone and split it into 3 distinct segments. But I needed a way to connect the printed segments. I wound up printing each piece with a hollow center, just large enough to accommodate a plastic peg or dowel that would join each pair of segments. The nice thing was, I could also use the printers to fabricate the dowels.”
After some creative engineering and required assembly, Gary printed a variation of the femur head that could be rotated to different positions. This enabled Snyder to simulate different structural deformations and the resulting pathologies in movement.
Next, Gary turned his attention to the scapula. Professor Snyder provided the original bone that would serve as a template for the 3D printout, which was small enough to be printed as a single unit. In this case, however, the Mcor printer proved to be a better choice because of its full color capabilities. Once the original bone had been scanned, creating the 3D replica was fairly straightforward.
It was at this point that Professor Snyder introduced a new element into the process. To create the variations he needed required the skills of Educational Applications Designer Jeff Macalino. Using the 3D modeling software Maya, he went to the original digital files created through the scanning process and redrew the coracoid process to simulate the other two variations. The result can be seen through a digital viewer here, and through the printouts shown below.
Gary Wisser: “Often an instructor has a bone that she wants to discuss, but it is difficult to show variations of that bone. Now we are able to scan a bone and create modified versions to represent normal clinical variations or pathology. Those bones can even be 3D printed adjusted during the lecture, as in the case of the femur, to illustrate the effect it would have on the surrounding structures and the health of the patient. With the scapula we made 3D prints of each so they could be held and discussed. We also created a virtual set of all three scapula that would allow them to be rotated in unison and compared on screen during a lecture or viewed from a web site by students during review.”
The femur and scapula prints have provided a good foundation for taking on similar 3D print challenges. In August, Dr. Rebecca Moellmer, Assistant Professor in the College of Podiatric Medicine, requested 25 models of a skeletal foot for her students, with moveable metatarsal longitudinal and oblique joints to illustrate different motions.
For more information on this project, please contact:
Steve Snyder, PT, DPT, CSCS, Assistant Professor, Department of Physical Therapy Education, College of Allied Health Professions, at email@example.com
Gary Wisser, 3D Visualization Specialist, at firstname.lastname@example.org