"You are not offering that suggestion as an explanation, are you?
Because it would require more explaining than the original problem.

And it is not even true.

Anatomically speaking, the knee-cap appertains to the thigh rather than to the shank.

It is a sesamoid bone belonging to the thigh muscles; yet in this case it has been left attached, apparently, to the shank.

No, Berkeley, that cat won't jump.