What does "loose-jointed" mean in this Sherlock Holmes passage?

Question

I’d like to ask about the following sentence from "The Three Garridebs" by Conan Doyle:

Mr. Nathan Garrideb proved to be a very tall, loose-jointed, round-backed person, gaunt and bald, some sixty-odd years of age.

I wanted to make sure what this loose-jointed means. Dictionaries say the word means:

A: supple and easy in movement
B: loosely built; with ill-fitting joints

But aren’t these meanings conflicting each other a bit? I don’t understand what exactly Doyle wanted to say about this Garrideb guy by the word. It mentioned earlier in the episode that Mr. Garrideb doesn’t go out often, or rather he stays indoors almost all the time. So maybe Watson (the writer of this memoir) thought he would be meeting a disabled person, but it turned out his body seemed to be just okay. Is this what Watson (or Doyle) wanted to tell readers here? I don’t know. Or this passage is to describe Mr. Garrideb looks lanky, even frail, as old man who always in his rooms should be?

Answer 1

The two meanings seem contradictory if you regard all joints as having the same function.

But think of it this way:

• the proper function of the joints of living creatures is movement.

• the proper function of most joints in things which are ‘built’ is usually to not move.

So a loose jointed table would tend to be unstable and perhaps prone to collapse, while a loose jointed person would move freely.

I’m not familiar with the storyline, but my expectation would be that Doyle wants us to understand that this isn’t an arthritic and creaky individual.