I hope this model isn't too gross to be hosted here :) If it is, I can take it down without any problem.

This is a more or less anatomically correct 3D model of a skull and brain. In fact it's my own skull and brain, I made the model based on my MRI data from a hospital. Of course this is not raw MRI data but a painstakingly hand-made model based on the data, created on top of segments from the voxel scans imported to Blender. These models have nice topology so they're easily usable in games. The file also includes the skin layer, i.e. my face, which you can ignore or use it as well, I don't care about "privacy" or anything similar. In case it ever matters, I hereby waive any personal rights.

All models together have nearly 6000 vertices and 12000 triangles. Only quad faces are used. There are no texture UVs or materials, just meshes. The blend file however has edge weights set for subdivision so you can easily make a higher poly models with the subdivision surface modifier. Sharp edges are also marked so that shading looks good.