At the WebGL Camp at SRI, Google's WebGL team demoed a web3D medical application called "Google Body Browser," which lets you explore the human body just like you can explore the world in Google Earth.
"Unlike other web based medical applications I have seen, no Flash, Java, or other plugins are needed. This application will run on any WebGL supported browser. (...) Last year I got the opportunity to work on an open standards based web3D medical app for learning the bones of the body. After witnessing how that app really helped students learn the bones, I am sold on using web3D for medical education," said Damon Hernandez.
You can now try Google Body Browser before it's added to Google Labs, assuming that you have a WebGL-enabled browser (it works well in Chrome 9 Dev Channel / Chrome Canary Build and it sort of works in Firefox 4 beta).
More Info: Google Body Browser