Employee was unloading cut slabs off saw cart. Co-worker was barring slabs apart. EE dropped wooden wedge into opening, stepped back to get off saw cart, missed step, fell backwards landing on butt, back & hitting head. Due to travel & COVID didn't see doctor until 12-4-20 for imaging. 12-14-20 appt diagnosed cervical strain & right wrist strain, requires therapy. No lost time.