1. Actual cause of death ain't always same as apparent cause of death
2. Any chemical alteration (Alcohol, Cocaine, Cannabis, McDonald's etc.)
3. Establishing or confirming time of death
4. In suspected homicides, can indicate some characteristics of assailant (e.g. height, right/left-handedness, strength etc.)
5. Some folks get off on cutting a big letter 'Y' into people (I know I always have)
6. Other evidence that can be aggregated (e.g pregnancy, chronic or terminal conditions at t.o.d.)
7. Can be required by Life Assurance firms if the deceased was heavily insured
8. Public Health records (Epidemiologists need data, dammit)
9. Any indications of other external infringements (hidden wounds, internal soft-tissue injuries, foreign body-fluids)
But mostly 5.
____________________________
"I started out with nothin' and I still got most of it left" - Seasick Steve