the internal width of the car from one internal door panels to the opposite panel
I think the internal parts of a car is the inside of the car for example engineand external parts of a car are the outer parts of the cars which can easily be seen for example doors, windows, bonnet and many other things.
DOOR, DOOR HANDLE, DOOR RUBBER, DOOR WINDOW
If you were looking for replacement car parts for your car door or other parts you could try a salvage yard. They have a lot of used cars there. You could also try Ebay.
on what kind of car
To find a model car door for your RC race car, you can search for parts using key words that pertain to the version of race car you have. You can either find parts in an area near you or from online sources.
Auto parts store.
Some car parts are the dashboard, defroster, diesel engine and dip stick.Some more are the door, door handle, drive belt, drive shaft and driver's seat.
It may be possible to reach and manipulate the door opening mechanism with the right kind of wrench, but you would have to examine the broken handle to see if internal mechanisms can be reached. Failing that, it could be necessary to cut away some of the door to get at the internal mechanism. A car repair company would probably advise you to just install a new door.
From the website Year one muscle car parts
look inside your car door. or at an auto parts store
Car parts that begin with the letter d:dashboard,defroster,dip stick,dome light,door,door handle,door locks,drive shaft,driver's seat,