The all-time WORST movie line ever. For two reasons:
1. It unncessarily alarms both the characters and the audience since we learn moments later that not only is his neck NOT broken but that the baby hasn't been injured in any way whatsoever.
2. Get a load of Maureen O'Hara's reaction when everyone comes rushing in to help the baby. She's like, "Neck? What broken neck?"
In an otherwise beautiful film, this line sticks out like a...a...a broken neck!
I realize how much time has past since your original post; however, if you are still interested:
That line came straight out of the book Spencer's Mountain by Earl Hamner, Jr. Most of the lines in the movie were verbatim from the book. The one glaringly altered line was when PattyCake was commenting on Clay Boy rubbing "ointment" on his body, the actual line was "why is Clay Boy rubbing Noczema on his fanny?" I guess in 1963 it was too soon for product placement in a movie and the word "fanny" would have been considered too vulgar for a family film.