HELP! 80's horror, campers in forest attacked by crazed mom, ankles kid at end?

[jshepard1]

I remember a crazed woman slicing a kid's ankle from under a hollowed out log or cave.  Its towards the end of the movie.  Some of the campers are talking about her as if she were a legend, and then a huge blade is seen coming out from underneath him, slicing his Achilles' tendon.  He falls and then she shows herself to the rest of the campers, screaming a hunter's warning at them.  I think one of the teenagers is actually her son?
Anything would help to relieve the broken fragments of so many horror movies I saw as a kid.

[Pamela3000]

There are soooo many slasher films involving campers!  Could you be thinking of the "Sleepaway Camp" films?  I believe there were 3 of them in the film series.  They were no "Friday the 13th" (the original version from the 80's) but they weren't too bad.