I just some tips and help with a dichotymus key I'm doing in anatomy. (i hope I'm spelling it correctly) concerning simple structures of the skeletal system.

Well there are 4 main classifications i chose to use; projections/processes, depressions/pits, cavities/passageways, and misc.

But I need help setting it up. Here is how i have started:

1a. If the structure is a process/projeciton..... line 2
1b. If the structure is not a process/projection..... line 3

2a. If the structure is ridge like..... crest.
2b. If the strucutre is not ridgelike.... line 4

3a. If the structure is a depression/pit.... line 5
.... etc etc etc.

I have i think 22 terms to describe (sinus, crest, fossa, fovea, etc) but is this layout okay or is there something more convenient/neat/preffered that i could use? This isnt much of an assignment, only bonus points (LOTS of points - and I get 4 days to do it)