ok...so i'm coding lesion excisions for the clavicle...would this area be considered part of the neck or trunk?

i was thinking more trunk area but my co-worker coder thinks it's neck since to him, the trunk starts at the chest, and to me,the trunk area starts at the neck base(clavicle)!

thanks for your input....and if you have any supporting documentations/link..that would even be better!