You could also use an 'image' type submit button.
if you have some html on your form, like this:
Code:
<INPUT type = 'image' source = 'bodypic.gif' name = 'imgbody'>
where 'bodypic.gif' is actually the name of your picture of a body, then, when the user clicks on the image, that submits the form. The image type submit button should give you x and y location variables for where in the image the person clicked.
I would have the user click on the picture of the body, then have your form processing script retrieve the x and y coords for the click, and display a curson on top of the pic (using absolute positioning css stuff) then ask them to click the 'submit' button if the right spot is click, or click again on the pick to change the location. Once the final submit is clicked, you can store the x and y coords in your database. Then, when someone needs to view the location of the injury, you can once again use css postitioning to display a cursor (or some other image, I use a transparent gif of crosshairs) at the injury location.
this lets you do the whole thing without image mapping, client side scripting, or special software.
hope this helps.