Friends and educators, I am asking for your help understanding what may be an idiomatic expression. I've searched your dictionary and various other sources online and I am completely stymied. The source of my confusion is a 1934 high school yearbook inscription. For clarity, this was printed by the authors of the yearbook, not penned in as a personal note.

The relevant portion begins as follows:
"Two winged feet, a little body, steady nerve, clear mind, even temper, and love of life. The feet carry him to success on the track. But what would they be without the rest?

(So far, so good: he was small-statured but an excellent runner; the last part implies that there was more to him than his fast feet. Here comes the confusing part.)

"The cradle has bent him around the well known thumb."

I have searched up and down for idioms about cradles AND bending AND thumbs, and nothing fits. I'm pretty well stuck on finding any existing usage of these terms together.

The only additional information I can offer that might help is that the high school was a military prep school in Virginia. So there might be some local word use at play here, or there might possibly be some military connotation to some of these words.

If it is NOT an idiomatic expression, but simply creative wordplay, I could possibly read into it that the "cradle" could be a reference to his upbringing, and the "thumb" might be referring to the people in charge of the school (keeping the students under their thumb). "To bend" could be used in the common sense, or the less frequent usages of "to devote one's attention to a task" or "to be forced to submit". Therefore, could the expression be taken, as a whole, to mean that his parents focused him on either complying with the rules of the military academy, or devoting his attention to it? That they say he was "BENT AROUND" the thumb instead of "UNDER" the thumb makes me think that he was made to work through or around the rigors of military academy instead of being crushed by it. Or, perhaps it's not a stretch to say the whole thing could be a euphemism and read between the lines to say two things: his parents had him "wrapped around the school's little finger" as we would say today--AND the school was an oppressive thumb.

Any help in deciphering this confounding use of English would be greatly appreciated. I've decoded Melvillean expressions with two and three levels of nested meaning more easily than this.