In fact, so much more necessary are those parts of the body which seem to be weaker.
Nay, much more those members of the body, which seem to be more feeble, are necessary:
But instead, there is [absolute] necessity for the parts of the body that are considered the more weak.
Nay, much rather, those members of the body which seem to be more feeble are necessary:
Instead, the parts of the body that people think are the weakest are the most necessary.