In 1801, three British artists, two painters, Benjamin West and James Cosway, and a sculptor, Thomas Banks, set out to test their belief in the inaccuracy of most depictions of the crucifixion. They were able to experiment using the corpse of an executed murderer, James Legg. At the time, the bodies of executed felons were the only legal source of "subjects" for anatomists, or in this case artists. They took the body of Legg from the gallows and nailed it to a cross, and flayed it. The gruesome result is shown in the picture below, taken when Legg was on display at the London Museum a few years ago. The experiment, however unpleasant, did show that traditional depictions of the crucifixion were anatomically incorrect.
Interestingly, an amazingly similar picture can be found in an illustration by the French artist Jacques Gamelin more than twenty years earlier (1779). Did Gamelin try the same experiment? Were the British artists influence by Gamelin? If anyone knows, I'd love to hear.