This depends on several factors: (1) Having osteoporosis; (2) A cement or concrete floor that is not wet; (3) How one falls and how one hits the floor; (4) Where did the fall happen? (5) The age of the person who falls.
(1) Havign osteoporosis means having poroous bones. Porous bones will break, even with a slight impact like inadvertently bumping into something hard.
(2) One tends to slip and slide on a wet floor, especially a wet wooden floor. One does not tend to slip and slide that much on a dry concrete floor. Such a fall by a person with osteoporosis may break 3 ribs depending on how the fall went down.
(3) How one falls and how one hits the floor will determine if bones will be broken. If one lands face down with a heavy impact, a fall from a relatively high place, say from a third or fourth storey window and falls flat on the hard pavement, rib bones will break.
(4) Where did the fall happen is important. A senior person stepping out of a bathtub trips on the edge of the tub and falls forward onto the tiled bathroom floor face down may break not only the neck bone but also the rib bones.
(5) The age of the person who falls is important since senior citizens generally have more brittle bones, or may have some osteoporosis, and are not drunk at the time. Studies have shown that a drunk does not suffer from broken bones in automobile accidents and car crashes as much as a sober person. The reason given was that the drunk cannot control and thus tighten the muscles and brace for impact. Thus the drunk’s body is “softer” and thus absorbs the impact better. A sober person’s muscles tighten up before impact and the impact is a hard hit and the bones crack and break.