My husband went to er for severe pain in his back; developed overnight. diagnosis from chest x-ray is "fracture of 6th posterior right rib laterally with callus formation which may represent subacute rib fracture. mild blunting of the right costophrenic

More info. needed .: . . . Hard to help without additional info. Callous formation implies healing. The real question is the cause, correct? Rib fractures rarely occur spontaneously (i.e. without a reason). If you are certain that there was no trauma involved, it is very important that your husband contact his doctor to be evaluated for the cause. I hope this helps. Best of luck.