It's a mistranslation. Yes, it's implied clearly enough in gender and age, but the anatomy in question was glossed over accidentally into a literary message.
It's old wives tails. ;)
Specifically, vetigial ones at that, what w/ the cookin' and cleanin', child rearin' and what not. Hard times back in those days so an extra hand became very useful, but they were still so busy, even w/ the extra appendage, that it didn't get recorded accurately in the annals of history.
Like "sharp as a knife". What a misnomer. I mean, it's pretty well established in its origins that if you outdressed someone in the gentry back in the day, you might get cut w/ a knife at the gala for such presumption as a means to secure their position as most fashionable alpha (fe)male of the soirre. Thusly, your attire is ruined w/ blood, so really, not looking too cosmopolitan.
This in turn coined the oft used term "fashion victim" too, but we got so caught up in the verbiage over the decades that we lost its meaning and the supporting players, the models got caught up in the confusion; "models doing runway" lost it's deeper meaning when, during the War Effort, alot of models were used on carrier and airport runways to help guide in errant aircraft that couldn't help but zero in on the eyecandy.