These vertebral stacking blocks fit together to form a three-quarter size spine model. See here for assembly video: https://youtu.be/z6MckyVLsLw

This model is designed as an interactive way to learn basic spinal anatomy. It is not suitable for young children. If you are looking for a more robust display model, you might consider this design: https://www.thingiverse.com/thing:4863003. If you are looking for a full-size model with more biomechanically accurate movement, you might consider this design: https://www.thingiverse.com/thing:4801717

With the exception of C1 and C2, vertebrae are numbered on the posterior aspect of the vertebral body. The numbers are to assist with assembly and are hidden in the final assembled model. There was only space for numbers, so you’ll have to learn what C1 and C2 look like and be able to differentiate between cervical, thoracic and lumbar vertebrae. (It’s not that hard!)

Every effort has been made to maintain anatomical accuracy; however some small modifications were necessary to optimize the files for printing. In particular, the bone around the transverse foramen in the cervical spine, and the articular processes and lamina of the cervical and upper thoracic vertebrae have been thickened.

Anatomically, the odontoid process of the C2 axis is held in place by the transverse ligament of the C1 atlas. In this model, the transverse ligament has been “ossified” leaving a hole for the odontoid process to click into place. This hole is intentionally tight to hold it in place. Expect to use a bit for force to snap them together, or file down the surfaces of the odontoid process as needed.

Male and female connectors have of course been added to each vertebral body.

Printing:

This is an intermediate project that requires good skills in setting up supports and in post-print cleaning and preparation.

The vertebrae in the files are oriented upside-down to print on the flat surface of the male connector. You will need to set up supports for the rest of the vertebral body. Be especially careful when setting up supports for the downward-oriented superior facet joints. “Tree” supports in Cura work well.

Assembly:

There are some important considerations for post-print clean-up of this model.

The fit between adjacent vertebra must be as tight as possible. Any movement between vertebra, especially the lower ones, will amplify up the spine and you will end up with an unstable spine with very poor posture!

When the pieces come of the print bed the first layer will be protruding out slightly, this is known as the “elephant’s foot.” If you try to connect the vertebra right off the print bed, this elephant’s foot will prevent the male piece from inserting. In order to achieve optimal fit, gradually file off the elephant’s foot while repeatedly attempting to connect the vertebra. As soon as you can forcefully insert the male piece, stop filing! The first few attempts to connect the vertebra should be very tight and difficult. After a few insertions, the surfaces will smooth out and you’ll be left with a nice tight connection.

Do not overdo the filing or you’ll be left with wiggly vertebrae!

Here are more of my anatomical designs you might enjoy:

Novelty:

Wearable Spine: https://www.thingiverse.com/thing:4982223
Skull Jewelry Set: https://www.thingiverse.com/thing:4980129
Happy Halloween Spine: https://www.thingiverse.com/thing:4979522
Eyeball Windchime: https://www.thingiverse.com/thing:4978632
Fingerbone Windchime: https://www.thingiverse.com/thing:4962956
Skull Windchime: https://www.thingiverse.com/thing:4962814
Creepy Custom Embossed Spine: https://www.thingiverse.com/thing:4916377
Mini Articulating Spine Keychain: https://www.thingiverse.com/thing:4891846
Big Bowl O’ Back Bones: https://www.thingiverse.com/thing:4881377
Vertebral Stacking Blocks: https://www.thingiverse.com/thing:4868387
Anatomically Correct Voronoi Heart: https://www.thingiverse.com/thing:4636146
Vertebrae with Secret Compartment: https://www.thingiverse.com/thing:4633188
Brain Puzzle: https://www.thingiverse.com/thing:4158232
Anatomical Heart Puzzle: https://www.thingiverse.com/thing:4146688

Educational:

6-Piece Magnetic Female Pelvis Model: https://www.thingiverse.com/thing:4946668
Fryette’s Laws Teaching Tool: https://www.thingiverse.com/thing:4887712
Hip and Pelvis Model: https://www.thingiverse.com/thing:4875641
Flexible Three-Quarter Spine Model with Display Stand: https://www.thingiverse.com/thing:4863003 Full Size Anatomically Correct Human Foot Model: https://www.thingiverse.com/thing:4849504
Full Size Anatomically Correct Human Hand Model: https://www.thingiverse.com/thing:4841107
Full Size Anatomically-Correct 18-Piece Magnetic Human Skull Model: https://www.thingiverse.com/thing:4830026
Full-sized Anatomically Correct Articulating Spine: https://www.thingiverse.com/thing:4801717
Articulating Lumbar Vertebrae: https://www.thingiverse.com/thing:4637241