I was suprised whan I found out peoples nerves don't always follow the same route. In the situation we are talking about here that nerve sometimes goes round on the outside of the elbow, and in other people can go on the inside of the elbow.
I've never had it diagnosed, but I suspect that I have this. Mainly if I've been doing a lot of DIY sort of stuff. never had it after playing bass though.
All basses, but especially 5 strings, should have graded ratios on the tuners. Ie the lower the note the higher the tuner ratio. It would make tuning those low notes a lot easier. Much less "'Shit, too far', start again"