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Learning about sex from a book, as a commentator on the long-extinct PBS television series Great American Dream Machine once said, is like learning how to fly by studying a pigeon that had been squashed by a truck. Fortunately for students of biology, learning anatomy on the Web by performing virtual dissections is not as hopeless an exercise. Of course, few would want a surgeon who learned anatomy solely from images conjured up on a 15-inch monitor with 256 colors and 800 x 600 pixels. A mouse, after all, is no substitute for a cadaver-cutting blade.
Still, for many who don't have
the inclination or the time to literally immerse themselves in their
subjects, online dissections provide a range of resources, from mere
diversions to professional reference material. The sights sampled here offer
material that ranges from photos of dissections to detailed guides to
projects as interactive as any you are likely to find on today's Web.
In a lab, students traditionally begin by dissecting frogs, so it might not be surprising to learn that frog dissections have attracted the attention of serious developers of virtual dissection sites. The Interactive Frog Dissection: An Online Tutorial is ideal for high school biology students. With many photographic illustrations and QuickTime movies, this site provides one of the most thorough dissections available online. Interactive directions, such as "click on the location at which you would begin the first incision," help make this site more "hands on" than many others. The graininess of the photographs is unfortunate, but that doesn't negate the many virtues of this virtual dissection experience.
The Virtual Frog Dissection Kit, from the
Lawrence Berkeley National Laboratory, is another
serious effort to provide an educational resource without pithing anything.
It uses computer-generated images of a frog rather than photographs. At
first this might be disappointing, but the originality of the approach
justifies it. For instance, it enables dissectors to go into "movie mode" to
"produce movies of the frog rotating in the direction chosen."
The site is part of the Whole Frog Project and includes the Virtual Frog Builder Game, a type of "reverse dissection." Starting with just the nerves, visitors have an opportunity to add organs and systems to the computer-generated amphibian. But, the site warns, "Don't try this until you have used the dissection kit awhile and gotten a good idea of where the organs are. Building a frog can be harder than it looks."
After you get your frog together, you can turn your attention to taking
apart a variety of different individual organs from different species. The
Cow's Eye Dissection
is one of
the most popular demonstrations at the hands-on Exploratorium,
according to this site's own description. The site offers a step-by-step guide with RealPlayer narration. If you have your own cow eye - which can be obtained from a butcher shop, slaughterhouse, or biological supply company - you are ready to follow along.
Several sites examine brain anatomy. For example, the Exploratorium also offers a visual tour of a sheep brain dissection. The Sheep Brain Dissection Guide from the University of Scranton Neuroscience Program provides a chance to follow structures through the brain from different directions and orientations. Virtual Hospital's The Human Brain: Dissections of the Real Brain represents more of a detailed and valuable atlas than a virtual dissection because it does not have interactive capabilities. But if you need to jump quickly to the superior cerebellar peduncle, or another favorite brain structure, you can do it easily here.
A whole-animal dissection is available at Cat Dissections Online, which is provided by students from the anatomy class at Berkeley High
School. This site offers detailed
procedures, with illustrations waiting behind highlighted words. Separate
pages cover various topics, including abdominal muscles
and nerves.
The Virtual Pig Dissection offers black-and-white drawings keyed to important anatomical landmarks. Clicking on the labels leads to definitions of the organs or structures.
Those seeking bigger game to dissect can turn to humans. Leicester University medical student Tim Taylor created the Virtual Autopsy site as a teaching
resource for preclinical medical students. It offers 12 autopsy cases, and an
opportunity to determine the cause of death for each one. The site also includes tutorials on basic
anatomy and physiology relevant to each case. The
photographs are of high quality and, although the site does not offer a full
human dissection, the autopsy examples provide interesting exercises for those who
want to play pathologist and learn something at the same time.
Human Anatomy Online seems to offer an interesting product in their "interactive cadaveric dissection tutorial," but you have to buy the CD-ROM. The free demo of their heart dissection is worth a visit. And yes, this is on the exam. A thorax quiz follows.
Today, there are other, less traditional ways to see what is inside a body
without cutting it open. Techniques like magnetic resonance imaging (MRI)
provide extraordinary, noninvasive diagnostic tools. Such techniques offer
ways to perform painless dissections of the living. For an overview
of the technology, visit The Basics of MRI, a site by Joseph P. Hornak
of the Rochester
Institute of Technology.
Finally, in the heavyweight division of dissections is the Visible Human Project, which is "creating complete, anatomically detailed, three-dimensional representations of the male and female human body."
Dean A. Haycock is a journalist who writes science articles for many magazines and newspapers. He received his Ph.D. in neuroscience from Brown University.
Caleb Brown is an illustrator and biologist living in Montana. By day he drives a delivery van, and by night he draws pictures with his computer.
Anatomically Correct: The Online Cat Dissection - provides a virtual dissection, labeled diagrams, and dissection movies.
Dissection of a Deer Tick - uses photomicrographs to show several steps in dissecting a tick.
FlyBrain - is an online atlas of the Drosophila nervous system, including photomicrographs of a variety of histological preparations.
Mickey: The Inside Story - uses labeled diagrams and descriptions to lead visitors through a mouse dissection step-by-step.
The Earthworm: Virtual Dissection - descriptions and pictures.
Starfish Dissection Tutorial - leads visitors through the internal and external structures with images and movies.
Web sites mentioned in this column: