This article is from the ER FAQ, by Rose Cooper firstname.lastname@example.org with numerous contributions by others.
The chain of command is very confusing. Donald Anspaugh is the
Chief of Staff, who is responsible for supervising all the medical
personnel in the hospital (and he happens to do a lot of surgery for
someone in this role); David Morganstern was the head of the Department
of Surgery, which apparently has oversight for the emergency department.
This makes some sense -- Weaver filled in as the Acting Director of
Emergency Services after David's heart attack, and this is a title which
would be in line with this hospital configuration. However, if he was
the head of the Department of Surgery, there should have been
someone else who was the Director of Emergency Services.
If that paragraph gave you a headache, take heart -- I've got one
too. I doubt that the writers have even figured this out; if one of you
is reading this right now, please e-mail me <email@example.com>, and
clear this up, because we're very, very confused. If you think you've
got it figured out, please e-mail me too, because my brain hurts.