This is reference imagery for characters showing unclothed anatomy, internal structures, etc.
For exterior reference like clothing, fur, feathers, etc., see Character Reference.
- Posemaniacs - rotatable anatomical models, lots of poses.
- Drawsh - anatomy and figure drawing
- ARTnatomy Artist friendly facial anatomy (start on level 2). A Flash-based web application that allows you to sort and isolate the muscles, skin and skull, with opacity controls.
- Andrew Loomis - figure drawing books
- Henry Gray - "Anatomy of the Human Body" /!\ Pop ups
- Rey Bustos - muscle and anatomy reference
- Facial muscles - interactive learning site
- Human anatomy references, also the online home of Andrew Loomis' figure drawing books.
- Henry Gray's Anatomy of the Human Body. Plenty of in-depth stuff on muscles and internal organs.