As I understand it, "blunt force trauma" is the expression used to indicate simply hitting something and getting bruised, etc. If you fell over and hit your head, it would be blunt force trauma. If you had a car crash, without your seatbelt on, you'd have blunt force trauma around your torso and face.

An elderly person falling down the stairs would very, very likely get blunt force trauma around the torso, like ribs, hips, stomach area.