My own attempt at this is available in the Wiki: http://basicroleplaying.com/wiki/doku.php?id=combat:major_wound_table
"S" denotes Serious wounds and "C" Critical wounds (though 'Grievous' may have been a better name, to avoid confusion with crit hits). What constitutes a Serious/Critical(Grievous) wound is a separate issue.
(I use a probably unusual system for HPs, where characters get only about half what's normal for BRP, but stay alive until -CON. In that -5hp is Serious and -10 is Critical/Grievous - and means they suffer the appropriate injury according to the location, and sub-location struck. But that's not necessary for using the table.)