So apparently neurology is a money pit for the hospital. Some bum cracks his head on the sewer grate when he passes out? Admit him to neuro. Some young girl with psych problems and no parents is faking seizures? Only one place to go! No one chooses neuro, neuro chooses you.
Apparently, orthopaedics is extremely lucrative. Old rich old lady wants a handcrafted hip? Bring her in! Some homeless guy has a bum knee? He can forget about it unless he has some infection ravaging his body, and then he is probably a medical patient with an ortho consult. Orthopaedics is like a surgical get-a-way for old people and golden young athletes; whoever has the time and money to get elective surgery. (In fairness, they also take some trauma patients and some medical overflow like the rest of us.)
Combine these two units, and who gets what they want from the brass?