Unlike most passenger aircraft, the supplemental oxygen mask system on the McDonnell Douglas DC-10 was located in the backs of passenger seats, rather than in an overhead compartment in the passenger service unit.
However, this seems to me like it wouldn't be possible to equip DC-10 aircraft with seatback inflight entertainment screens, since there'd be no space in the seatback headrest to hold the required electronics for a display screen as it'd all be taken up by the oxygen system.
I've seen this video, which shows seatback screens on an MD-11, which I think is simply a stretched DC-10, and looking closely I think the supplemental oxygen is located in the standard spot, overhead in the passenger service unit. I think the position must have changed for the MD-11 aircraft.
Was it possible for airlines to equip the DC-10 with seatback IFE screens? Was there an option to have oxygen masks in the standard overhead spot? Or did no airline ever equip their DC-10 with seatback screens?