A Skiatook man was treated for head, arm, and internal injuries following a Wednesday evening accident in Osage County.  The Oklahoma Highway Patrol reports that 49 year-old David Curtis Sampson, Jr. was driving westbound on State Highway 20 just before 11 o'clock.  The report shows he was driving too fast for conditions on a wet roadway with defective tires with low tread depth.  Sampson lost control and went into a broad slide, going off the roadway to the left and the truck hit a tree.  A 13 year-old was in the truck.  Skiatook ambulance took the teen to St. Francis Hospital where they were admitted in stable condition with head, and internal injuries.  Neither occupant was wearing a seatbelt.