So: acute.

Less than a week.

Almost certainly less than seventy-two hours.

And, taken together with the described behaviour, consistent with an event that happened during the night of the tenth into the morning of the eleventh.

For the ribs.

Three posterior rib fractures, left side, sixth, seventh and eighth, all with callus of similar maturity, estimated at two to five weeks.

And here is the thing about posterior rib fractures in infants that I did not know and that changed how I understood the whole year.