I can guess. There's a sudden spasm of pain in this area, followed by paralysis of one side, probably the right.
8 seconds sound clip from the El Dorado (1966) movie soundboard.
You can hear this line at 01:37:28 in the Blu-ray version of the movie.
Quote context
[...]
- I reckon he's got a more interesting misery than you got, Sheriff.
- Look, Doctor, I don't want to take up your time, but mine's still bleeding.
- You've got nothing to worry about, Sheriff. It's a good, clean wound.
- Tell me, it's giving you trouble, isn't it?
- Why don't you tell him the truth?
- Well, it doesn't last very long.
- But it lasts a little longer each time. Doesn't it?
- What are you trying to tell him, Doctor?
- McLeod may settle the whole problem for us.
- If I'm here after this is all over, I'll come and see you, Doc. I promise.
- Now, Doctors, if you please, could one of you step over here so that I could rest my finger?
[...]